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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2016	Mar. 03, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	Mirna Therapeutics, Inc.
Entity Central Index Key	0001527599
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 60.5
Common Stock Outstanding		20,856,693
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 16,432	$ 89,713
Short-term marketable securities	44,066	0
Prepaid expenses and other current assets	882	829
Total current assets	61,380	90,542
Property and equipment, net	354	375
Restricted cash	2,432	0
Total assets	64,166	90,917
Current Liabilities:
Accounts payable	361	3,687
Accrued expenses	2,400	2,214
Total current liabilities	2,761	5,901
Lease obligations, long-term	1,053	0
Total liabilities	3,814	5,901
Stockholders’ Equity (Deficit):
Preferred stock, $0.001 par value, 5,000,000 authorized at December 31, 2016 and 2015; 0 shares outstanding at December 31, 2016 and 2015	0	0
Common stock, $0.001 par value; 250,000,000 shares authorized at December 31, 2016 and 2015; 20,841,393 shares issued and outstanding at December 31, 2016; 20,830,555 shares issued and outstanding at December 31, 2015	21	21
Additional paid in capital	163,126	161,518
Accumulated deficit	(102,791)	(76,523)
Other comprehensive loss	(4)	0
Total stockholders’ equity	60,352	85,016
Total liabilities and stockholders’ equity	$ 64,166	$ 90,917

Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	20,841,393	20,830,555
Common stock, shares outstanding (in shares)	20,841,393	20,830,555

Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
Research and development	$ 13,930	$ 18,947	$ 10,545
General and administrative	8,118	6,080	3,369
Restructuring charges	4,442	0	0
Loss on disposal of assets	128	0	0
Write-off of offering costs	0	0	1,920
Total operating expenses	26,618	25,027	15,834
Other income:
Interest income	350	44	0
Net loss	(26,268)	(24,983)	(15,834)
Less: Accretion and dividends on convertible preferred stock	0	(4,320)	(2,824)
Net loss attributable to common stockholders	(26,268)	(29,303)	(18,658)
Other Comprehensive Loss:
Unrealized loss on available-for-sale securities, net of tax	(4)	0	0
Total other comprehensive loss	$ (26,272)	$ (29,303)	$ (18,658)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (1.26)	$ (5.85)	$ (291.00)
Common shares used to compute basic and diluted net loss per share attributable to common stockholders (in shares)	20,833,963	5,010,323	64,131

Statements of Stockholder's Equity (Deficit) - USD ($) $ in Thousands	Total	Initial Public Offering	Private Placement	Common Stock	Common Stock Initial Public Offering	Common Stock Private Placement	Additional Paid-in Capital	Additional Paid-in Capital Initial Public Offering	Additional Paid-in Capital Private Placement	Accumulated Deficit	Other Comprehensive Income
Balance at Dec. 31, 2013	$ (29,914)			$ 0			$ 890			$ (30,804)	$ 0
Balance (in shares) at Dec. 31, 2013				2,061
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options	209			$ 0			209
Exercise of stock options (in shares)				80,816
Issuance of common stock	4			$ 0			4
Issuance of common stock (in shares)				448
Stock-based compensation	408						408
Series C dividends	(2,824)						(1,511)			(1,313)
Net loss	(15,834)									(15,834)
Balance at Dec. 31, 2014	(47,951)			$ 0			0			(47,951)	0
Balance (in shares) at Dec. 31, 2014				83,325
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options	67			$ 1			66
Exercise of stock options (in shares)				28,516
Issuance of common stock		$ 43,664	$ 16,616		$ 7	$ 2		$ 43,657	$ 16,614
Issuance of common stock (in shares)					6,954,962	2,395,010
Stock-based compensation	985						985
Accretion of convertible preferred stock	(449)						(180)			(269)
Series C & Series D dividends	(3,871)						(551)			(3,320)
Conversion of preferred stock	100,938			$ 11			100,927
Conversion of preferred stock (in shares)				11,368,742
Net loss	(24,983)									(24,983)
Balance at Dec. 31, 2015	$ 85,016			$ 21			161,518			(76,523)	0
Balance (in shares) at Dec. 31, 2015	20,830,555			20,830,555
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options	$ 9			$ 0			9
Exercise of stock options (in shares)				5,313
Stock-based compensation	1,592						1,592
Issuance of stock under Employee Stock Purchase Plan	7			$ 0			7
Issuance of stock under Employee Stock Purchase Plan (in shares)				5,525
Other comprehensive loss	(4)										(4)
Net loss	(26,268)									(26,268)
Balance at Dec. 31, 2016	$ 60,352			$ 21			$ 163,126			$ (102,791)	$ (4)
Balance (in shares) at Dec. 31, 2016	20,841,393			20,841,393

Statements of Stockholder's Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Initial Public Offering
Offering cost	$ 5,021
Private Placement
Offering cost	$ 149

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (26,268)	$ (24,983)	$ (15,834)
Adjustment to reconcile net loss to net cash used in operating activities:
Restructuring charges	4,442	0	0
Depreciation and amortization	159	54	35
Stock-based compensation	1,592	985	408
Issuance of stock for services	0	0	4
Amortization of premiums/ discounts on marketable securities	260	0	0
Loss on disposal of assets	128	0	0
Changes in operating assets and liabilities:
Grant reimbursement and other receivables	(160)	119	40
Prepaid expenses and other current assets	107	(650)	(99)
Deferred offering costs	0	0	105
Other noncurrent assets	0	0	17
Accounts payable	(3,264)	2,816	189
Accrued expenses	(1,801)	524	1,165
Net cash used in operating activities	(24,805)	(21,135)	(13,970)
Investing activities
Purchases of marketable securities	(103,114)	0	0
Maturities of marketable securities	58,784	0	0
Restricted cash	(2,432)	0	0
Purchase of property and equipment	(1,729)	(251)	(102)
Net cash used in investing activities	(48,491)	(251)	(102)
Financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	0	41,433	0
Proceeds from the issuance of common stock, net of issuance costs	0	60,280	0
Proceeds from the exercise of stock options	16	67	209
Cash provided by financing activities	16	101,780	209
Net increase (decrease) in cash and cash equivalents	(73,280)	80,394	(13,863)
Cash and cash equivalents at beginning of period	89,713	9,319	23,182
Cash and cash equivalents at end of period	16,432	89,713	9,319
Supplemental disclosure of non-cash investing and financing activities
Conversion of preferred stock to common stock	$ 0	$ 100,938	$ 0

Organization	12 Months Ended
Organization	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Nature of business Mirna Therapeutics, Inc. (“Mirna” or “the Company”) is a biopharmaceutical company focused on microRNA-based oncology therapeutics. The Company was incorporated in Delaware in December 2007 as a wholly‑owned subsidiary of Asuragen, Inc. (“Asuragen”) and was spun out to existing Asuragen stockholders in December 2009. Following the close of the Company's Phase 1 clinical trial of MRX34 in September 2016, the Company is evaluating its strategic alternatives focusing on enhancing stockholder value, including the possibility of a merger or sale of the Company, and has discontinued further research and development activities (see Note 13) to reduce operating expenses while it evaluates these opportunities. The Company is located in Austin, Texas. In October 2015, the Company sold 6,250,000 shares of common stock, $0.001 par value per share, in an underwritten public offering (the “IPO”) and 2,395,010 shares of common stock in a concurrent private placement, with both offerings at a price of $7.00 per share. The underwriters of the IPO purchased an additional 704,962 shares of common stock pursuant to their option to purchase additional shares. The Company’s aggregate net proceeds from the IPO were $43.7 million, after deducting the transaction offering costs and the underwriting discounts incurred. The Company also received net proceeds of $16.7 million after deducting the offering transaction costs from the concurrent private placement. The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are uncertainties of technological innovations, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company believes that its cash, cash equivalents and marketable securities of $60.5 million at December 31, 2016 will enable the Company to maintain its current and planned operations for at least the next twelve months.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Use of estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires the Company’s management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.

Prior to the IPO on October 6, 2015, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. The board of directors determined the estimated fair value of the Company’s common stock based on a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector and the prices at which the Company sold shares of convertible preferred stock, the superior rights and preferences of securities senior to its common stock at the time and the likelihood of achieving a liquidity event, such as an initial public offering or sale of the Company.

Prior to its IPO, the Company utilized various valuation methodologies in accordance with the framework of the American Institute of Certified Public Accountants, or AICPA, Audit and Accounting Practice Aid Series: Valuation of Privately Held Company Equity Securities Issued as Compensation, or the AICPA Practice Aid, to estimate the fair value of its common stock. The methodologies included the Option Pricing Method utilizing the Backsolve Method (a form of the market approach defined in the AICPA Practice Aid) and the Probability‑Weighted Expected Return Method based upon the probability of occurrence of certain future liquidity events such as an initial public offering or sale of the Company. Each valuation methodology includes estimates and assumptions that require the Company’s judgment. Significant changes to the key assumptions used in the valuations could result in different fair values of common stock at each valuation date.

Research and development costs

Research and development costs consist of costs the Company incurred for its own research and development activities and for preclinical studies and clinical trials. Research and development costs include salaries and personnel‑related costs, consulting fees, fees paid for contract research services, the costs of laboratory equipment and facilities, license fees and other external costs. These research and development costs are expensed when incurred.

The Company records upfront and milestone payments made to third parties under licensing arrangements as an expense. Upfront payments are recorded when incurred and milestone payments are recorded when the specific milestone has been achieved.

The Company accounts for government grants as a reduction of research and development expenses. Government grants are recorded at the time the related research and development costs have been incurred by the Company and, accordingly, become eligible for reimbursement. The Company accrues for government grants that have been earned but not yet received.

Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are deferred and capitalized. The capitalized amounts are expensed as the related goods are delivered or the services are performed.

Stock‑based compensation

The Company accounts for its stock‑based compensation awards in accordance with ASC Topic 718, Compensation—Stock Compensation (“ASC 718”). ASC 718 requires all stock‑based payments to employees, including grants of employee stock options, to be recognized in the statements of operations based on their grant date fair values. For stock options granted to employees and to members of the board of directors for their services on the board of directors, the Company estimates the grant date fair value of each option award using the Black‑Scholes option‑pricing model. The use of the Black‑Scholes option‑pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk‑free interest rates and expected dividend yields of the common stock. For awards subject to service‑based vesting conditions, the Company recognizes stock‑based compensation expense, net of estimated forfeitures, equal to the grant date fair value of stock options on a straight‑line basis over the requisite service period.

Clinical trial and pre-clinical study accruals

Prior to the discontinuation of the Company's research and development activities, the Company estimated pre-clinical study and clinical trial expenses pursuant to contracts with research institutions and contract research organizations that conducted and managed pre-clinical studies and clinical trials on the Company’s behalf. These estimates were based on the level of service performed and the underlying agreement. Further, the Company accrued expenses related to clinical trials based on the level of patient enrollment and other activities according to the related agreements. The Company monitored patient enrollment levels and other activities to the extent reasonably possible and adjusted estimates accordingly. If actual costs incurred or the timing of services varied from the Company's estimate, the Company adjusted the accrual accordingly. On September 20, 2016 the Company announced its decision to close the ongoing Phase 1 study of MRX34 and halted enrollment and dosing of patients in the study.

Restructuring

Following the closing of the Phase 1 MRX34 clinical trial, the Company implemented a workforce reduction in the fourth quarter of 2016 to reduce operating expenses while it evaluates strategic alternatives. The majority of severance and benefits payments were settled during the first quarter of 2017. The Company entered retention agreements with key employees necessary to close the Phase 1 clinical trial of MRX34 if employees remained with the Company until June 30, 2017 or were terminated by the Company without cause prior to such date. The Company has recognized the restructuring liability for such retention agreements over the employees' service period.

In accordance with ASC 420, Exit and Disposal Cost Obligations, the Company has also recognized contract termination costs in connection with a leased property it intended to occupy as its corporate headquarters and research facility, as well as a temporary lab in use prior to the discontinuation of the Company's research and development activities. In addition, the Company has recognized asset impairments related to its lab equipment used in the Phase 1 clinical trial, construction in process, and other property and equipment for which the Company does not expect to receive a future benefit.

Amounts recorded in restructuring charges can result from a complex series of judgments about future events and uncertainties and can heavily rely on estimates and assumptions.

Income taxes

Income taxes are recorded in accordance with ASC 740, Accounting for Income Taxes (“ASC 740”), which provides for deferred taxes using an asset and liability approach. The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. The Company determines its deferred tax assets and liabilities based on differences between financial reporting and tax bases of assets and liabilities, which are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. Valuation allowances are provided if, based upon the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.

The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740. When uncertain tax positions exist, the Company recognizes the tax benefit of tax positions to the extent that the benefit will more likely than not be realized. The determination as to whether the tax benefit will more likely than not be realized is based upon the technical merits of the tax position as well as consideration of the available facts and circumstances. As of December 31, 2016 and 2015, the Company does not have any significant uncertain tax positions.

Comprehensive loss

Comprehensive loss is composed of net loss and other comprehensive income or loss. Other comprehensive loss consists of unrealized gains and losses on marketable securities.

Cash and cash equivalents

The Company considers highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Cash equivalents, which consist primarily of cash, money market funds and U.S. treasury and agency securities with a maturity of less than 90 days when purchased, are stated at fair value.

Concentrations of credit risk

Financial instruments that potentially subject the Company to credit risk consist primarily of cash and cash equivalents and short-term marketable securities. The Company holds these investments in U.S. treasury and agency securities and highly‑rated corporate debt securities, and limits the amounts of credit exposure to any one financial institution. These amounts at times may exceed federally insured limits. The Company has not experienced any credit losses in such accounts and does not believe it is exposed to any significant credit risk on these funds. The Company has no off‑balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements.

At December 31, 2016, available-for-sale securities are invested in U.S. treasury and agency securities and highly-rated corporate debt securities that had a maturity date of three months or greater when acquired. As discussed in Note 3, the fair value of these securities was $44.1 million, or $4,000 less than their original par value purchase price.

Fair value measurements

The Company records money market funds at fair value. ASC Topic 820, Fair Value Measurements and Disclosures, establishes a fair value hierarchy for those instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). The hierarchy consists of three levels:


•	Level 1—Unadjusted quoted prices in active markets for identical assets or liabilities.


•	Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.


•	Level 3—Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

The carrying amounts reflected in the balance sheets for cash, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their fair values at December 31, 2016 and 2015, due to their short‑term nature.

There have been no changes to the valuation methods during the years ended December 31, 2016 and 2015. The Company evaluates transfers between levels at the end of each reporting period. There were no transfers of assets or liabilities between Level 1, Level 2 or Level 3 during the years ended December 31, 2016 or 2015.

Marketable securities

Marketable securities with maturities at purchase beyond one year, but less than twenty-four months, may be classified as short-term marketable securities based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Marketable securities with maturities at purchase beyond twenty-four months are classified as non-current. Available-for-sale securities are maintained by an investment manager and may consist of U.S. Treasury securities and government agency securities and corporate debt securities. Available-for-sale securities are carried at fair value with the unrealized gains and losses included in other comprehensive loss as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in other income.

If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other-than-temporary” and, if so, mark the investment to market through a charge to the Company’s statement of operations and comprehensive loss.

Restricted cash

Restricted cash consists of cash amounts held for specific or limited purposes and, therefore, not available for general operating activities. In June 2016, the Company secured a standby letter of credit of $2.4 million for the benefit of the landlord for the Company's lease of approximately 23,578 square feet of office and laboratory space in the event of default. The restricted cash consists of cash providing security under the terms of the lease described in Note 13.

Property and equipment

Property and equipment consist of laboratory equipment, computer equipment and software, leasehold improvements, furniture and fixtures and office equipment. Property and equipment are stated at cost and depreciated using the straight‑line method over the estimated useful lives of the respective assets:




● Laboratory equipment		5-7 years
● Computer equipment and software		3 years
● Leasehold improvements		shorter of asset’s useful life or remaining term of lease
● Furniture and fixtures		5 years
● Office equipment		5 years

Costs of major additions and betterments are capitalized; maintenance and repairs, which do not improve or extend the life of the respective assets, are charged to expense as incurred. Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and the resulting gain or loss is recognized.

Impairment of long‑lived assets

The Company periodically evaluates its long‑lived assets for potential impairment in accordance with ASC Topic 360, Property, Plant and Equipment. Potential impairment is assessed when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recovered. Recoverability of these assets is assessed based on undiscounted expected future cash flows from the assets, considering a number of factors, including past operating results, budgets and economic projections, market trends and product development cycles. If impairments are identified, assets are written down to their estimated fair value. The Company recognized an impairment charge of $1.4 million for the year ended December 31, 2016.

Offering costs

Deferred offering costs, which consist of direct incremental legal and professional accounting fees relating to preferred stock private placements and initial public offerings, are capitalized. The deferred offering costs are offset against the proceeds from the offering upon the consummation of the offering. In 2014, the Company’s initial public offering was delayed and the deferred offering costs for that offering in the amount of $1,920,000 were expensed.

Segment and geographic information

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, or decision making group, in making decisions on how to allocate resources and assess performance. The Company’s chief operating decision maker is the chief executive officer. The Company and the chief operating decision maker view the Company’s operations and manage its business as one operating segment. The Company operates in only one geographic segment.

Net loss per share attributable to common stockholders

Prior to the IPO, the Company used the two‑class method to compute net loss per common share attributable to common stockholders because the Company has issued securities, other than common stock, that contractually entitle the holders to participate in dividends and earnings of the Company. The two‑class method requires earnings for the period to be allocated between common stock and participating securities based upon their respective rights to receive distributed and undistributed earnings. Historically, holders of the Company’s Series A, Series B, Series B‑1, Series C and Series D convertible preferred stock were entitled, on a pari passu basis, to receive dividends when, as and if declared by the board of directors, prior and in preference to any declaration or payment of any dividend on the common stock until such time as the total dividends paid on each share of Series C and Series D convertible preferred stock is equal to its cumulative dividends. The Series A, Series B and Series B‑1 convertible preferred stock would also be entitled to the dividend amount paid to common stockholders on an as‑if‑converted‑to‑common stock basis. As a result, all series of the Company’s convertible preferred stock were considered participating securities. All of the Company’s outstanding preferred stock was converted to common stock in connection with the IPO in October 2015.

Under the two‑class method, for periods with net income, basic net income per common share is computed by dividing the net income attributable to common stockholders by the weighted‑average number of shares of common stock outstanding during the period. Net income attributable to common stockholders is computed by subtracting from net income the portion of current year earnings that the participating securities would have been entitled to receive pursuant to their dividend rights had all of the year’s earnings been distributed. No such adjustment to earnings is made during periods with a net loss, as the holders of the participating securities have no obligation to fund losses. Diluted net loss per common share is computed by using the weighted‑average number of shares of common stock outstanding. Due to net losses for the years ended December 31, 2016, 2015, and 2014, basic and diluted net loss per share attributable to common stockholders were the same, as the effect of all potentially dilutive securities would have been anti‑dilutive.

Recent accounting pronouncements

In March 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share Based Payment Accounting ("ASU 2016-09") as part of the FASB simplification initiative. The new standard provides for changes to accounting for stock compensation including 1) excess tax benefits and tax deficiencies related to share-based payment awards will be recognized as income tax expense in the reporting period in which they occur; 2) excess tax benefits will be classified as an operating activity in the statement of cash flow; 3) the option to elect to estimate forfeitures or account for them when they occur; and 4) increase tax withholding requirements threshold to qualify for equity classification. ASU 2016-09 is effective for public companies for annual periods, and interim periods within those annual periods, beginning after December 15, 2016, and early adoption is permitted. The Company is currently evaluating the impact that ASU 2016-09 will have on the financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The new standard requires the recognition of assets and liabilities arising from lease transactions on the balance sheet and the disclosure of key information about leasing arrangements. Accordingly, a lessee will recognize a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. Both the asset and liability will initially be measured at the present value of the future minimum lease payments over the lease term. Subsequent measurement, including the presentation of expenses and cash flows, will depend on the classification of the lease as either a finance or an operating lease. Initial costs directly attributable to negotiating and arranging the lease will be included in the asset. For leases with a term of twelve months or less, a lessee can make an accounting policy election by class of underlying asset to not recognize an asset and corresponding liability. Lessees will also be required to provide additional qualitative and quantitative disclosures regarding the amount, timing and uncertainty of cash flows arising from leases. These disclosures are intended to supplement the amounts recorded in the financial statements and provide additional information about the nature of an organization’s leasing activities. The new standard is effective for fiscal years beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. In transition, lessees are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The transition guidance also provides specific guidance for sale and leaseback transactions, build-to-suit leases and amounts previously recognized in accordance with the business combinations guidance for leases. The Company is currently evaluating our expected adoption method and the impact of this new standard on the financial statements.

In August 2014, the FASB issued ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. The ASU is intended to define management’s responsibility to evaluate whether there is substantial doubt about an organization’s ability to continue as a going concern and to provide related footnote disclosures. For all entities, the ASU is effective for annual periods ending after December 15, 2016 and interim periods within annual periods beginning after December 15, 2016. The Company adopted this standard in 2016.

Fair Value Measurements

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value Measurements

The following sets forth the Company's assets that are measured at fair value on a recurring basis as of December 31, 2016 and December 31, 2015:



	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
December 31, 2016
Assets:
Cash and Cash Equivalents
Cash	$	2,785	$	2,785	—		—
Money market funds	9,647		$	9,647	—		—
US government agency securities and treasuries	4,000		—		4,001
Total cash and cash equivalents	16,432		12,432		4,001		—
Marketable securities
U.S. government agency securities and treasuries	42,512		—		42,512		—
Corporate debt securities	1,554		—		1,554		—
Total marketable securities	44,066		—		44,066		—
Restricted cash	2,432		2,432		—		—
Total assets	$	62,930	$	14,864	$	48,067	$	—

December 31, 2015
Assets:
Money Market Funds	89,713		89,713		—		—
Total Assets	$	89,713	$	89,713	$	—	$	—

Cash and cash equivalents

The Company considers all highly liquid securities with original final maturities of three months or less from the date of purchase to be cash equivalents. As of December 31, 2016 and December 31, 2015, cash and cash equivalents are comprised of cash, money market accounts, U.S. government agency securities and corporate debt securities.

Marketable securities.

The cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At December 31, 2016, the balance in the Company’s accumulated other comprehensive loss was composed solely of activity related to the Company’s available-for-sale marketable securities. The Company has not realized material gains or losses on sales of available-for-sale investment securities during any of the periods presented.

As of December 31, 2016, available for sale securities of approximately $15.4 million were in an unrealized loss position of $7,700. The Company has the intent and ability to hold such securities until recovery. The Company determined that there were no material changes in the credit risk of the above investments. The Company did not hold any investments with an other-than-temporary impairment as of December 31, 2016 and December 31, 2015.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Marketable Securities

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

The following table summarizes the available-for-sale securities held at December 31, 2016 (in thousands):



December 31, 2016	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities and treasuries	$	42,516	$	4	$	(8	)	$	42,512
Corporate debt securities	1,554		—		—			1,554
Total available-for-sale securities	$	44,070	$	4	$	(8	)	$	44,066

The Company did not have available for sale securities at December 31, 2015. There were no available for sale securities held as of December 31, 2016 with maturities greater than one year.

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Property and Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment consisted of the following (in thousands):



	December 31,			December 31,
	2016			2015
Machinery, computers and equipment	$	385		$	687
Leasehold improvements	—			18
Accumulated depreciation	(31		)	(330		)
	$	354		$	375

Depreciation expense was $159,000, $54,000 and $35,000 in 2016, 2015 and 2014, respectively.

Accrued Expenses

12 Months Ended

Dec. 31, 2016

Payables and Accruals [Abstract]

Accrued Expenses

Accrued expenses

Accrued expenses consist of the following (in thousands):



	December 31,
	2016		2015
Accrued restructuring	$	1,609	$	—
Professional fees	259		437
Clinical trial costs	220		489
Compensation and related items	154		1,151
Other	158		137
	$	2,400	$	2,214

Included in accrued restructuring are severance and benefits of approximately $1,097,000 and the current portion of contract termination costs related to a leased facility of $512,000. See Note 9 for additional discussion.

Shareholders' Equity	12 Months Ended
Shareholders' Equity	Dec. 31, 2016
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Common Stock The voting, dividend and liquidation rights of holders of shares of common stock are subject to and qualified by the rights, powers and preferences of the holders of shares of convertible preferred stock. The Company’s common stock has the following characteristics: The holders of shares of common stock are entitled to one vote for each share of common stock held at all meetings of stockholders and written actions in lieu of meetings. The holders of shares of common stock are entitled to receive dividends, if and when declared by the Company’s board of directors. Cash dividends may not be declared or paid to holders of common stock until paid on each series of outstanding convertible preferred stock in accordance with their respective terms. As of December 31, 2016, no cash dividends have been declared or paid since the Company’s inception. Reverse Stock Split In September 2015, the stockholders approved a reverse stock split of the outstanding shares of the Company’s common stock, Series A convertible preferred stock, Series B convertible preferred stock, Series B-1 convertible preferred stock, Series C convertible preferred stock and Series D convertible preferred stock in which every 15 shares were converted into one share of the related stock. No fractional shares were issued as a result of the reverse stock split. The par value for each class of stock remained at $0.001 per share. The effect of the reverse stock split has been recognized retroactively, in all share and price per share data presented in the financial statements and the notes to the financial statements. Offerings In September 2015, the Company entered into a new grant contract with Cancer Prevention and Research Institute of Texas (“CPRIT”) in connection with an award of approximately $16.8 million. The 2015 award was in the form of an agreement by CPRIT to purchase $16.8 million of shares of common stock of the Company in a private placement concurrent with the initial public offering of the Company’s common stock. On October 5, 2015, CPRIT purchased 2,395,010 shares of the Company’s common stock at $7.00 per share. Net proceeds from the private placement, after related transaction offering costs, were approximately $16.6 million. In October 2015, the Company issued 6.25 million shares of common stock in an underwritten public offering, with a price of $7.00 per share. The underwriters purchased an additional 704,962 shares of common stock pursuant to their options to purchase additional shares. The Company received aggregate net proceeds of approximately $43.7 million in the public offering, after deducting the underwriting discounts and commissions and estimated offering expenses payable by the Company.

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

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+ Details

Stock Option Plans

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Option Plans

2008 Long Term Incentive Plan

During 2008, the Company adopted the 2008 Long Term Incentive Plan, which allows for incentive stock options for its employees and nonqualified stock options (inclusive of restricted stock units and stock appreciation rights) (the “2008 Plan”) for employees and nonemployees under which an aggregate of 330,582 stock options and stock purchase rights may be granted. In December 2013, the total amount available for grant under the 2008 Plan was increased by 224,200 to 554,782. In March 2014, the Company’s board of directors approved an increase of 115,153 shares available for grant pursuant to the 2008 Plan to 669,935. In March 2015, the total amount of available to grant under the 2008 Plan was increased in conjunction with the Company’s offering of Series D preferred stock by 391,650 shares to 1,061,585. Options under the 2008 Plan have a maximum life of 10 years. Options vest at various intervals, as determined by the Company’s board of directors at the date of grant.

2015 Equity Incentive Plan

In August 2015, the Company’s board of directors approved the 2015 Equity Incentive Award Plan, (the “2015 Plan”), which was effective in connection with the pricing of the IPO on September 30, 2015. The 2015 Plan provides for the granting of a variety of stock‑based compensation awards, including stock options, stock appreciation rights, or SARs, restricted stock awards, restricted stock unit awards, deferred stock awards, dividend equivalent awards, stock payment awards, performance awards and other stock‑based awards. The 2015 Plan is the successor to the 2008 Plan and the 706,656 options outstanding in the 2008 Plan at December 31, 2016 may be transferred to the 2015 Plan if awards thereunder terminate, expire or lapse for any reason without the delivery of shares to the holder thereof. As of December 31, 2016, 88,510 shares have been transferred from the 2008 Long Term Incentive Plan to the 2015 Equity Incentive Plan for awards that have terminated, expired or lapsed. Under the 2015 Plan, 1,671,800 shares of the Company’s common stock were initially authorized and reserved for issuance. In addition, 1,041,526 shares of the Company's common stock were authorized and reserved for issuance in the first quarter of 2016, for a total of 2,801,836 authorized for grant under the 2015 Plan at December 31, 2016.

2015 Employee Stock Purchase Plan

In August 2015, the Company’s board of directors approved the 2015 Employee Stock Purchase Plan (the “ESPP”), which was effective in connection with the pricing of the IPO on September 30, 2015. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP generally provides for set offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. Employees exercised their option to purchase 5,525 shares of common stock under the ESPP as of December 31, 2016. Shares available for future purchase under the ESPP were 369,960 at December 31, 2016; however, the Company has suspended future issuances of Mirna Therapeutics, Inc. common stock under the ESPP plan.

Stock Option Activity

The Company’s stock option activity for the years ended December 31, 2016, 2015, and 2014 was as follows:



			Weighted‑
			Average		Weighted‑Average
	Number		Exercise		Contractual
	of Shares		Price		Life (years)
Outstanding at December 31, 2013	354,833		$	2.40	8.80
Granted	234,447		8.10
Exercised	(80,816	)	2.40
Forfeited/canceled	(7,553	)	4.70
Outstanding at December 31, 2014	500,911		4.95		8.85
Granted	1,057,082		6.82
Exercised	(28,516	)	2.36
Forfeited/canceled	(18	)	7.50
Outstanding at December 31, 2015	1,529,459		6.28		9.00
Granted	928,250		4.41
Exercised	(5,313	)	1.65
Forfeited/canceled	(547,182	)	6.26
Outstanding at December 31, 2016	1,905,214		$	5.39	7.49
Options Exercisable at December 31, 2016	838,922		$	5.45	5.57

The total intrinsic value of options exercised during the years ended December 31, 2016, 2015 and 2014 was $13,000, $160,000, and $383,000, respectively. The intrinsic value of options exercisable and total options outstanding at December 31, 2016 was $28,000 and $28,000, respectively. The total fair value of options vested during the years ended December 31, 2016, 2015 and 2014 was $1,524,000, $858,000 and $198,000, respectively.

Stock Based Compensation Expense

Total stock‑based compensation expense was allocated as follows (in thousands):



	Year Ended
	December 31,
	2016		2015		2014
Research and development expense	$	372	$	306	$	110
General and administrative expense	1,220		679		298
	$	1,592	$	985	$	408

There was approximately $3.5 million of unrecognized compensation cost related to the stock options granted under the 2015 Plan, which is expected to be amortized over the next 2.6 years. There were no restricted stock units or stock appreciation rights granted under the 2015 Plans of December 31, 2016.

The fair value of each stock option award is estimated on the date of grant using the Black‑Scholes option‑pricing model that uses the assumptions noted in the table below. Expected volatility for the Company’s common stock was determined based on an average of the historical volatility of a peer group of similar companies. The Company has limited stock option exercise information. Accordingly, the expected term of stock options granted was calculated using the simplified method, which represents the average of the contractual term of the stock option and the weighted‑average vesting period of the stock option. The assumed dividend yield is based upon the Company’s expectation of not paying dividends in the foreseeable future. The risk‑free rate for periods within the expected life of the stock option is based upon the U.S. Treasury yield curve in effect at the time of grant.

The assumptions used in the Black‑Scholes option‑pricing model for stock option grants during the years ended December 31, 2016, 2015 and 2014 are as follows:



	Year Ended December 31,
	2016	2015	2014
Expected life (in years)	5.5 - 6.1	5.9 - 6.7	5.8-6.1
Risk‑free interest rate	1.1% - 1.6%	1.6% - 2.0%	1.8% - 2.8%
Expected volatility	76.9% - 79.5%	77.5% - 84.7%	75.3% - 85.4%
Expected dividend yield	—	—	—
Weighted-average grant date fair value per share	$2.97	$4.73	$5.40

No related tax benefits were recognized for the years ended December 31, 2016, 2015 or 2014.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Restructuring Charges

12 Months Ended

Dec. 31, 2016

Restructuring and Related Activities [Abstract]

Restructuring Charges

On September 20, 2016, Mirna announced its decision to close the ongoing Phase 1 study of MRX34 and voluntarily halted the enrollment and dosing of patients in the study. Following the announcement, the Company received verbal notice from the U.S. Food and Drug Administration ("FDA") on September 28, 2016 that its Investigational New Drug MRX34 had been placed on full clinical hold. Following the Company's announcement and notification from the FDA, Mirna's Board of Directors approved a reduction of the total number of full-time employees from 36 to 12. The Company also committed to retention payments to certain key employees if such employees remained with the Company until June 30, 2017 or were terminated by Mirna without cause prior to such date. Restructuring charges are expected to be incurred through June 30, 2017 and total approximately $4.7 million, including non-cash impairment charges of $1.4 million.

Restructuring charges were as follows (in thousands):



	Year ended December 31, 2016
Employee severance and related costs	$	1,554
Contract termination costs	1,486
Asset impairment costs	1,402
Total restructuring charges	$	4,442

There were no restructuring charges for the year ended December 31, 2015.

The accrued restructuring activity during the year ended December 31, 2016 was as follows (in thousands):



	Employee severance and related costs			Contract Termination Costs		Total
Balance at December 31, 2015	—			—		—
Restructuring Charge	$	1,554		$	1,486	$	3,040
Cash payments	(457		)	—		(457		)
Other (1)	—			79		79
Balance at December 31, 2016	$	1,097		$	1,565	$	2,662

(1) Other includes the effect of historical deferred rent and prepaid balances recognized under the leases terminated under contract termination costs.

Employee severance and related costs

Of the total accrued restructuring balance of $2.7 million, approximately $1.6 million has been presented as a current liability and $1.1 million has been presented as a long-term liability. Employee severance and benefits costs recorded in restructuring charges for the year ended December 31, 2016 included $1.5 million in employee severance and benefits costs and $0.1 million for accrued retention payments which are being recognized over the respective employee's service period.

Contract termination costs

Contract termination costs recorded in restructuring charges for the year ended December 31, 2016 of $1.5 million related to the Company's determination to cease use and not occupy the Company's headquarters and research facility in connection with the lease the Company entered into in June 2016 (see Note 14). In connection with this determination, the Company recorded a liability of $1.6 million, which is equal to the fair value of the lease obligation at the cease-use date of November 20, 2016, after adjusting for the effects of prepaid and deferred rent balances related to the lease, of which $1.1 million has been recorded as a long term liability in the balance sheets within Lease obligations. The Company estimated the liability for the contract termination costs associated with the lease as of the cease-use date based on the discounted present value of the remaining lease payments, considering future estimated sublease income, estimated broker fees and contractual executory costs.

Asset impairment costs

Following the discontinuation of research and development activities and corresponding workforce reduction, the Company determined that certain property and equipment was impaired and recognized an impairment charge of $1.4 million in restructuring expense in the statement of operations for the year ended December 31, 2016. Of the total impairment charge, approximately $555,000 relates to the impairment of lab equipment which had a salvage value of $320,000 based on a third party appraisal of the lab equipment, which was sold for $325,000 in February 2017 (see Note 17). In addition, the Company recognized an impairment of $591,000 in construction in progress for the Company's planned headquarters and research facility associated with the termination of the lease contract discussed above. Further, following the workforce reduction, the Company sold or donated its remaining office equipment with the exception of nominal office equipment necessary to continue administrative functions and the closure of its Phase 1 clinical trial, resulting in an impairment of furniture, computers and equipment and leasehold improvements of $256,000.

Income Taxes

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

The Company recorded no provision for income taxes as of December 31, 2016 due to reported net losses since inception.

A reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company’s effective income tax rate is as follows for the years ended December 31, 2016, 2015 and 2014 (in thousands):



	2016			2015			2014
Income tax benefit computed at federal statutory tax rate	$	(8,931	)	$	(8,494	)	$	(5,383	)
Change in valuation allowance	9,287			9,002			5,675
General business credits	(572		)	(661		)	(386		)
Other	216			153			94
Total	$	—		$	—		$	—

The Company has established a valuation allowance due to uncertainties regarding the realization of deferred tax assets based upon the Company’s lack of earnings history. During the year ended December 31, 2016, the valuation allowance increased by $9.3 million. Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2016 and 2015 are as follows (in thousands):



	2016			2015
Net operating loss carryforwards	$	27,518		$	19,562
Depreciation and amortization	1,367			1,207
Stock‑based compensation	597			260
Credit carryforwards	1,717			1,147
Prepaid expenses	—			—
Accrued liabilities	538			264
Total deferred tax assets	31,737			22,440
Valuation allowance	(31,737		)	(22,440		)
Net deferred tax asset	$	—		$	—

As of December 31, 2016 and 2015, the Company had net operating loss (“NOL”) carryforwards for federal income tax purposes of approximately $80.9 million and $57.5 million, respectively. As of December 31, 2016 and 2015, the Company also had available research and development tax credits for federal income tax purposes of approximately $1,441,000 and $985,000, respectively. If not utilized, these carryforwards expire at various dates beginning in 2028. As of December 31, 2016, the Company had state research and development tax credit carryforwards of approximately $267,000, which will begin to expire in 2024 if not utilized.

Utilization of the NOL carryforwards and tax credit carryforwards may be subject to a substantial annual limitation due to ownership change limitations that have occurred previously or that could occur in the future, as provided by Section 382 of the Internal Revenue Code of 1986 (“Section 382”), as well as similar state provisions. Ownership changes may limit the amount of NOL carryforwards and tax credit carryforwards that can be utilized annually to offset future taxable income and tax, respectively. In general, an ownership change, as defined by Section 382, results from transactions that increase the ownership of 5% shareholders in the stock of a corporation by more than 50 percentage points in the aggregate over a three‑year period. The Company has not performed a study to determine whether any ownership change has occurred since the Company’s formation through December 31, 2016. However, the Company believes that it has experienced at least one ownership change in the past and that it may experience additional ownership changes as a result of subsequent shifts in its stock ownership. Should there be an ownership change that has occurred or will occur, the Company’s ability to utilize existing carryforwards could be substantially restricted.

The Company applies the accounting guidance in ASC 740 related to accounting for uncertainty in income taxes. The Company’s reserves related to taxes are based on a determination of whether, and how much of, a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. As of December 31, 2016 and 2015, the Company had no unrecognized tax benefits. During the years ended December 31, 2016 and 2015, the Company had no interest and penalties related to income taxes.

The Company files income tax returns in the U.S. federal and Texas jurisdictions. As of December 31, 2016, the statute of limitations for assessment by the Internal Revenue Service (“IRS”) is open for the 2013 and subsequent tax years, although carryforward attributes that were generated for tax years prior to then may still be adjusted upon examination by the IRS if they either have been, or will be, used in a future period. The 2012 and subsequent tax years remain open and subject to examination by the State of Texas. There are currently no federal or state income tax audits in progress.

Shared Services Agreement with Asuragen	12 Months Ended
Shared Services Agreement with Asuragen	Dec. 31, 2016
Related Party Transactions [Abstract]
Shared Services Agreement with Asuragen	Shared Services Agreement with Asuragen On November 3, 2009, the Company entered into an agreement with Asuragen under which Asuragen shares space with and provides services to the Company in support of the Company’s business. Such services have included human resources, finance and accounting, information technology, purchasing, shipping and receiving, equipment use, and various facility expenses. The Company pays Asuragen a monthly service fee for the services provided by Asuragen to the Company, which does not include direct charges incurred by Asuragen on behalf of the Company. The Company paid Asuragen approximately $316,000, $490,000 and $506,000 for the years ended December 31, 2016, 2015 and 2014, respectively. On October 31, 2014, the Company entered into a sublease agreement with Asuragen for use of office, laboratory and shared space. Total rent expense was approximately $59,000 and $89,000 for the year ended December 31, 2016 and 2015, respectively. Both the lease and the shared service agreements expired on August 31, 2016.

Retirement Plan	12 Months Ended
Retirement Plan	Dec. 31, 2016
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Retirement Plan	Retirement Plan The Company sponsors a defined contribution plan that provides all eligible employees an opportunity to accumulate funds for retirement. Employees who have completed 90 days of service and are at least 21 years of age may contribute to this plan, and these contributions are matched by the employer on a basis that is determined annually by the Company’s board of directors. The Company may also make profit sharing contributions to the plan. Employer contributions for 2016, 2015 and 2014 were approximately $169,000, $117,000 and $91,000, respectively.

License Agreements	12 Months Ended
License Agreements	Dec. 31, 2016
License Agreements
License agreements	License Agreements Rosetta Genomics Ltd. In December 2015, the Company entered into a Patent License Agreement (the “License Agreement”) with Rosetta Genomics Ltd. (“Rosetta”), licensing to the Company certain patents owned or controlled by Rosetta as specified in the License Agreement. Under the License Agreement, Rosetta has granted the Company a non-assignable, non- transferable, worldwide license for certain patents in connection with the development and commercialization of products that relate to the tumor suppressor microRNA MIR-34 (“Products”). This license is exclusive with respect to Products that relate to MRX34, the Company’s first product candidate which has been placed on full clinical hold by the Food & Drug Administration ("FDA") and non-exclusive for products that are not related to MRX34. Under the License Agreement, the Company paid Rosetta an up-front, non- refundable payment of $1.6 million in January 2016, which was accrued as an expense within research and development for the year ended December 31, 2015. The Company shall also be obligated to pay low single- digit royalties on net sales of Products, as well as royalties on sublicense revenues. Certain development and regulatory milestone payments totaling $3 million may also be payable in connection with specified types of Products, upon the achievement of certain development and/ or regulatory milestone events. Marina Biotech, Inc. In December 2011, the Company entered into a licensing agreement with Marina, pursuant to which Marina granted to the Company a license to liposomal delivery technology, NOV340, known under the brand name “SMARTICLES,” to develop and commercialize drug products incorporating Marina’s delivery system exclusively in combination with the Company’s first therapeutic product, MRX34, which has been placed on full clinical hold by the FDA. In December 2013, the license agreement was amended to include three additional specific mimics selected by the Company to use with SMARTICLES on an exclusive basis, and in May 2015, the license agreement was further amended to reduce the amount of a specific milestone payment and to provide for the prepayment of such milestone payment. In August 2015, the Company also entered into a side letter to the license agreement, under which it exercised its right to select an additional specific microRNA, in exchange for the payment of a specified selection fee payment. The Company has cumulatively paid Marina approximately $2.1 million through December 31, 2016 in up‑front and milestone payments and as consideration for the inclusion within the license of four additional microRNA compounds. Although the Company has discontinued its research and development activities, the Company would be required to make payments to Marina based upon the achievement of certain development and regulatory milestones, totaling up to $6 million in the aggregate for each licensed product. The Company has agreed to pay up to an additional $4 million per licensed product upon the achievement of certain regulatory milestones for a specified number of additional indications, leading to a maximum cap on all milestone payments of $10 million per product. The exception to this is for the Company’s first therapeutic product, MRX34, where the aggregate of all remaining development and regulatory milestone payments due to Marina, including for all additional indications, is $4.0 million. In addition to milestone payments, the Company will be required to pay low single digit royalties on net sales of licensed products other than MRX34, subject to customary reductions and offsets. As a result of the Company’s 2013 amendment to the agreement with Marina, the Company is no longer required to pay a royalty to Marina with respect to sales of the Company’s first therapeutic product, MRX34. If the Company sublicenses its rights under the license from Marina, for each optioned microRNA compound covered by such sublicense the Company is required to pay a specified lump‑sum payment representing the remainder of the selection fee for the inclusion of such microRNA compound within the scope of the license agreement, as well as a portion of any revenue the Company receives from such sublicensees at a tiered percentage between the very low single digits and the mid‑teens, depending on the circumstances in which the sublicense is entered into. Yale University In 2006, Asuragen entered into an exclusive license agreement with Yale University (“Yale”) under certain patent rights relating to microRNAs arising from the laboratory of Dr. Frank Slack. This agreement was assigned to the Company by Asuragen in connection with the Company’s acquisition of certain assets, including patent rights, in 2009. In February 2014, the Company as successor‑in‑interest to Asuragen, amended and restated the exclusive license agreement. Some of the patent filings in the Company’s intellectual property portfolio that are licensed to the Company by Asuragen are also included in the patents licensed under the agreement with Yale. The Company will be required to pay royalties to Yale on net sales of licensed products that contain specified microRNAs, at a percentage ranging from the very low to the low single digits, subject to customary reductions and offsets. The Company will also be required to pay to Yale a portion of specified gross revenue that the Company receives from the Company’s sublicensees at a percentage in the mid‑single digits. The Company will be required to make payments for achievement of certain development and regulatory milestones by products containing one specified microRNA and covered by the licensed patents, of up to $600,000 in the aggregate for each such product, subject to reduction in certain circumstances. In addition, the Company is required to pay an annual license maintenance fee and minimum annual royalties under certain circumstances. The Company provided Yale University with notice of termination effective March 2017, following the discontinuation of its research and development activities.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Operating Lease

In June 2016, the Company entered into a lease for its corporate headquarters and research facility in Austin, Texas (the “Headquarters”) under an operating lease agreement (the “Lease”). The Lease commenced on January 1, 2017 (the "Commencement Date"). The initial term of the lease is for a 123 month period, with the option to extend the lease for up to two consecutive 60 month terms. Rent expense under the Lease for year ended December 31, 2016 through the cease-use date discussed in Note 9 was approximately $165,000.

The Lease provides annual base rent of approximately $600,000 in the first year after a three-month rent-free period following the Commencement Date, with subsequent annual increases of approximately 3% in the annual base rent. In connection with the Lease, the landlord has provided a tenant improvement allowance of approximately $1.9 million to be used by the Company to build-out certain improvements to the Headquarters. The Lease also provides for an additional improvement allowance of up to $1.3 million. The additional allowance, if exercised, will amortize over 120 months on a straight-line basis. There have been no draws on the additional improvement allowance as of December 31, 2016.

Mirna has obtained a standby letter of credit for the initial amount of approximately $2.4 million (the "Letter of Credit"), which may be drawn down by the landlord in the event of default. If Mirna meets certain requirements, the amount due under the Letter of Credit may be reduced to approximately $800,000.

In November 2016, following the workforce reduction described in Note 8, the Company determined to cease use and not occupy the headquarters and research facility under the Lease. See Note 9 to the financial statements for further information on the accounting for the Lease.

Under the Lease, future minimum payments payable are approximately as follows:



	Operating
Period ending December 31,	Lease
2017	$	450,929
2018	614,855
2019	633,364
2020	652,340
2021 and thereafter	4,565,888
Total	$	6,917,376

CPRIT

In August 2010, the Company entered into a grant contract with the Cancer Prevention and Research Institute of Texas (CPRIT), under which it received a $10.3 million commercialization award from the State of Texas through CPRIT. CPRIT was established to expedite innovation and commercialization in the area of cancer research and to enhance access to evidence-based prevention programs and services throughout the State of Texas. The award was a three-year award that was funded annually, and the contract terminated on January 31, 2014, subject to the Company's obligations to make certain payments that survive termination. Under the terms of the award, the Company will be required to pay to CPRIT a portion of the Company's revenues from sales of certain products by the Company, or received from our licensees or sublicensees, at a percentage in the low single digits until the aggregate amount of such payments equals a specified multiple of the grant amount, and thereafter at a rate of less than one percent, subject to the Company's right, under certain circumstances, to make a one-time payment in a specified amount to CPRIT to buy out such payment obligations. The 2010 grant contract also contains a provision that provides for repayment to CPRIT some amount not to exceed the full amount of the grant proceeds under certain specified circumstances involving relocation of our principal place of business outside Texas.

Legal Contingencies

The Company does not currently have any contingencies related to ongoing legal matters.

Net Loss Per Share Attributable to Common Stockholders

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Net Loss Per Share Attributable to Common Stockholders

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share data):



	Year Ended December 31,
	2016			2015			2014
Net loss	$	(26,268	)	$	(24,983	)	$	(15,834	)
Accretion of convertible preferred stock to redemption value	—			(449		)	—
Accrued dividends on convertible preferred stock	—			(3,871		)	(2,824		)
Net loss attributable to common stockholders—basic and diluted	(26,268		)	(29,303		)	(18,658		)
Weighted-average number of common shares—basic and diluted	20,833,963			5,010,323			64,131
Net loss per share attributable to common stockholders—basic and diluted	$	(1.26	)	$	(5.85	)	$	(291.00	)

The following potentially dilutive securities outstanding, prior to the use of the treasury stock method or if‑converted method, have been excluded from the computation of diluted weighted‑average common shares outstanding, because including them would have had an anti‑dilutive effect due to the losses reported.



	December 31,
	2016	2015	2014
Convertible preferred stock	—	7,921,490	5,599,939
Stock options	1,905,214	1,529,459	500,911
	1,905,214	9,450,949	6,100,850

Selected Quarterly Data (unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Data (unaudited)

The following table contains quarterly financial information for 2016 and 2015. The operating results for any quarter are not necessary indicative of results for any future period.



	2016 Quarter Ended
	December 31			September 30			June 30			March 31
Operating Expenses:
Research and development	$	2,341		$	3,384		$	3,682		$	4,523
General and administrative	1,999			1,940			2,049			2,130
Restructuring charges	4,442			—			—			—
Loss on disposal of assets	—			128
Total operating expenses	8,782			5,452			5,731			6,653
Other (income)	(88		)	(87		)	(93		)	(82		)
Net loss	(8,694		)	(5,365		)	(5,638		)	(6,571		)
Net loss per share attributable to common stockholders—basic and diluted	(0.42		)	(0.26		)	(0.27		)	(0.32		)



	2015 Quarter Ended
	December 31			September 30			June 30			March 31
Operating Expenses:
Research and Development	$	6,363		$	4,683		$	4,499		$	3,402
General and Administrative	2,462			1,556			1,185			877
Total operating expenses	8,825			6,239			5,684			4,279
Other (income)	(36		)	(8		)	—			—
Net loss	(8,789		)	(6,231		)	(5,684		)	(4,279		)
Net loss attributable to common stockholders	(8,890		)	(7,785		)	(7,229		)	(5,397		)
Net loss per share attributable to common stockholders—basic and diluted	(0.45		)	(82.16		)	(78.87		)	(60.99		)

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Sale of Lab Equipment In February 2017, the Company entered into an Asset Purchase Agreement for the sale of the Company's Lab Equipment with a third party for cash consideration of $325,000. The selling price of the Lab Equipment approximated its book value at December 31, 2016.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Use of estimates

Research and development costs

Stock-based compensation

Stock‑based compensation

Clinical trial and pre-clinical study accruals

Restructuring

Amounts recorded in restructuring charges can result from a complex series of judgments about future events and uncertainties and can heavily rely on estimates and assumptions.

Income taxes

Comprehensive loss

Comprehensive loss is composed of net loss and other comprehensive income or loss. Other comprehensive loss consists of unrealized gains and losses on marketable securities.

Cash and cash equivalents

Concentrations of credit risk

Fair value measurements


•	Level 1—Unadjusted quoted prices in active markets for identical assets or liabilities.


•	Level 2—Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability.


•	Level 3—Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

Marketable securities

Restricted cash

Property and equipment




● Laboratory equipment		5-7 years
● Computer equipment and software		3 years
● Leasehold improvements		shorter of asset’s useful life or remaining term of lease
● Furniture and fixtures		5 years
● Office equipment		5 years

Impairment of long-lived assets

Impairment of long‑lived assets

Offering costs

Segment and geographic information

Net loss per share attributable to common stockholders

Recent accounting pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Schedule of useful life of property and equipment

Property and equipment are stated at cost and depreciated using the straight‑line method over the estimated useful lives of the respective assets:




● Laboratory equipment		5-7 years
● Computer equipment and software		3 years
● Leasehold improvements		shorter of asset’s useful life or remaining term of lease
● Furniture and fixtures		5 years
● Office equipment		5 years

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Schedule of Company's Assets Measured at Fair Value on a Recurring Basis

The following sets forth the Company's assets that are measured at fair value on a recurring basis as of December 31, 2016 and December 31, 2015:



	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)
December 31, 2016
Assets:
Cash and Cash Equivalents
Cash	$	2,785	$	2,785	—		—
Money market funds	9,647		$	9,647	—		—
US government agency securities and treasuries	4,000		—		4,001
Total cash and cash equivalents	16,432		12,432		4,001		—
Marketable securities
U.S. government agency securities and treasuries	42,512		—		42,512		—
Corporate debt securities	1,554		—		1,554		—
Total marketable securities	44,066		—		44,066		—
Restricted cash	2,432		2,432		—		—
Total assets	$	62,930	$	14,864	$	48,067	$	—

December 31, 2015
Assets:
Money Market Funds	89,713		89,713		—		—
Total Assets	$	89,713	$	89,713	$	—	$	—

Marketable Securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Summary of Available-for-Sale Securities Held

The following table summarizes the available-for-sale securities held at December 31, 2016 (in thousands):



December 31, 2016	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
U.S. government agency securities and treasuries	$	42,516	$	4	$	(8	)	$	42,512
Corporate debt securities	1,554		—		—			1,554
Total available-for-sale securities	$	44,070	$	4	$	(8	)	$	44,066

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Schedule of property and equipment

Property and equipment consisted of the following (in thousands):



	December 31,			December 31,
	2016			2015
Machinery, computers and equipment	$	385		$	687
Leasehold improvements	—			18
Accumulated depreciation	(31		)	(330		)
	$	354		$	375

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2016

Payables and Accruals [Abstract]

Schedule of accrued expenses

Accrued expenses consist of the following (in thousands):



	December 31,
	2016		2015
Accrued restructuring	$	1,609	$	—
Professional fees	259		437
Clinical trial costs	220		489
Compensation and related items	154		1,151
Other	158		137
	$	2,400	$	2,214

Stock Option Plans (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of stock option activity

The Company’s stock option activity for the years ended December 31, 2016, 2015, and 2014 was as follows:



			Weighted‑
			Average		Weighted‑Average
	Number		Exercise		Contractual
	of Shares		Price		Life (years)
Outstanding at December 31, 2013	354,833		$	2.40	8.80
Granted	234,447		8.10
Exercised	(80,816	)	2.40
Forfeited/canceled	(7,553	)	4.70
Outstanding at December 31, 2014	500,911		4.95		8.85
Granted	1,057,082		6.82
Exercised	(28,516	)	2.36
Forfeited/canceled	(18	)	7.50
Outstanding at December 31, 2015	1,529,459		6.28		9.00
Granted	928,250		4.41
Exercised	(5,313	)	1.65
Forfeited/canceled	(547,182	)	6.26
Outstanding at December 31, 2016	1,905,214		$	5.39	7.49
Options Exercisable at December 31, 2016	838,922		$	5.45	5.57

Schedule of stock-based compensation expense for employee stock options, allocation of expense in statement of operations

Total stock‑based compensation expense was allocated as follows (in thousands):



	Year Ended
	December 31,
	2016		2015		2014
Research and development expense	$	372	$	306	$	110
General and administrative expense	1,220		679		298
	$	1,592	$	985	$	408

Schedule of assumptions used in the Black-Scholes option-pricing model for stock option grants

The assumptions used in the Black‑Scholes option‑pricing model for stock option grants during the years ended December 31, 2016, 2015 and 2014 are as follows:



	Year Ended December 31,
	2016	2015	2014
Expected life (in years)	5.5 - 6.1	5.9 - 6.7	5.8-6.1
Risk‑free interest rate	1.1% - 1.6%	1.6% - 2.0%	1.8% - 2.8%
Expected volatility	76.9% - 79.5%	77.5% - 84.7%	75.3% - 85.4%
Expected dividend yield	—	—	—
Weighted-average grant date fair value per share	$2.97	$4.73	$5.40

Restructuring Charges (Tables)

12 Months Ended

Dec. 31, 2016

Restructuring and Related Activities [Abstract]

Restructuring Charges

The accrued restructuring activity during the year ended December 31, 2016 was as follows (in thousands):



	Employee severance and related costs			Contract Termination Costs		Total
Balance at December 31, 2015	—			—		—
Restructuring Charge	$	1,554		$	1,486	$	3,040
Cash payments	(457		)	—		(457		)
Other (1)	—			79		79
Balance at December 31, 2016	$	1,097		$	1,565	$	2,662

(1) Other includes the effect of historical deferred rent and prepaid balances recognized under the leases terminated under contract termination costs.

Restructuring charges were as follows (in thousands):



	Year ended December 31, 2016
Employee severance and related costs	$	1,554
Contract termination costs	1,486
Asset impairment costs	1,402
Total restructuring charges	$	4,442

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Reconciliation of the expected income tax benefit (expense) computed using the federal statutory income tax rate to the Company's effective income tax rate



	2016			2015			2014
Income tax benefit computed at federal statutory tax rate	$	(8,931	)	$	(8,494	)	$	(5,383	)
Change in valuation allowance	9,287			9,002			5,675
General business credits	(572		)	(661		)	(386		)
Other	216			153			94
Total	$	—		$	—		$	—

Schedule of components of the Company's deferred tax assets and liabilities

Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2016 and 2015 are as follows (in thousands):



	2016			2015
Net operating loss carryforwards	$	27,518		$	19,562
Depreciation and amortization	1,367			1,207
Stock‑based compensation	597			260
Credit carryforwards	1,717			1,147
Prepaid expenses	—			—
Accrued liabilities	538			264
Total deferred tax assets	31,737			22,440
Valuation allowance	(31,737		)	(22,440		)
Net deferred tax asset	$	—		$	—

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments Payable

Under the Lease, future minimum payments payable are approximately as follows:



	Operating
Period ending December 31,	Lease
2017	$	450,929
2018	614,855
2019	633,364
2020	652,340
2021 and thereafter	4,565,888
Total	$	6,917,376

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of computation of basic and diluted net loss per share

The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share data):



	Year Ended December 31,
	2016			2015			2014
Net loss	$	(26,268	)	$	(24,983	)	$	(15,834	)
Accretion of convertible preferred stock to redemption value	—			(449		)	—
Accrued dividends on convertible preferred stock	—			(3,871		)	(2,824		)
Net loss attributable to common stockholders—basic and diluted	(26,268		)	(29,303		)	(18,658		)
Weighted-average number of common shares—basic and diluted	20,833,963			5,010,323			64,131
Net loss per share attributable to common stockholders—basic and diluted	$	(1.26	)	$	(5.85	)	$	(291.00	)

Schedule of potentially dilutive securities excluded from the computation of weighted average common shares outstanding



	December 31,
	2016	2015	2014
Convertible preferred stock	—	7,921,490	5,599,939
Stock options	1,905,214	1,529,459	500,911
	1,905,214	9,450,949	6,100,850

Selected Quarterly Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Data (unaudited)

The following table contains quarterly financial information for 2016 and 2015. The operating results for any quarter are not necessary indicative of results for any future period.



	2016 Quarter Ended
	December 31			September 30			June 30			March 31
Operating Expenses:
Research and development	$	2,341		$	3,384		$	3,682		$	4,523
General and administrative	1,999			1,940			2,049			2,130
Restructuring charges	4,442			—			—			—
Loss on disposal of assets	—			128
Total operating expenses	8,782			5,452			5,731			6,653
Other (income)	(88		)	(87		)	(93		)	(82		)
Net loss	(8,694		)	(5,365		)	(5,638		)	(6,571		)
Net loss per share attributable to common stockholders—basic and diluted	(0.42		)	(0.26		)	(0.27		)	(0.32		)



	2015 Quarter Ended
	December 31			September 30			June 30			March 31
Operating Expenses:
Research and Development	$	6,363		$	4,683		$	4,499		$	3,402
General and Administrative	2,462			1,556			1,185			877
Total operating expenses	8,825			6,239			5,684			4,279
Other (income)	(36		)	(8		)	—			—
Net loss	(8,789		)	(6,231		)	(5,684		)	(4,279		)
Net loss attributable to common stockholders	(8,890		)	(7,785		)	(7,229		)	(5,397		)
Net loss per share attributable to common stockholders—basic and diluted	(0.45		)	(82.16		)	(78.87		)	(60.99		)

Organization (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2015
Subsidiary, Sale of Stock [Line Items]
Par value (in dollars per share)		$ 0.001	$ 0.001		$ 0.001
Cash, cash equivalents, and marketable securities		$ 60.5
Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)				448
Initial Public Offering \| Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)	6,250,000		6,954,962
Par value (in dollars per share)	$ 0.001
Share price (in dollars per share)	$ 7.00
Proceeds from issuance of common stock in initial public offering	$ 43.7
Over-Allotment Option \| Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)	704,962
Private Placement \| Common Stock
Subsidiary, Sale of Stock [Line Items]
Shares issued (in shares)	2,395,010		2,395,010
Proceeds from issuance of common stock in private placement	$ 16.7
Minimum
Subsidiary, Sale of Stock [Line Items]
Number of months company can maintain its current and planned operations		12 months

Summary of Significant Accounting Policies - Other (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2016 USD ($) ft²
Accounting Policies [Abstract]
Fair value of available-for-sale securities	$ 44,066,000
Fair value of available-for-sale securities, amount less than original par value purchase price	4,000
Transfers in and out of assets and liabilities measured at fair value on a recurring basis using Level 1, Level 2 and Level 3 inputs.	0	$ 0
Line of Credit Facility [Line Items]
Area of company's lease (in sq ft) \| ft²				23,578
Impairment charge	$ 1,402,000
Deferred offering costs expensed			$ 1,920,000
Number of operating segments \| segment	1
Number of geographic segments \| segment	1
Standby Letters of Credit
Line of Credit Facility [Line Items]
Standby letter of credit	$ 2,400,000			$ 2,400,000.0

Summary of Significant Accounting Policies - Property and equipment (Details)	12 Months Ended
	Dec. 31, 2016
Laboratory equipment \| Minimum
Property and equipment
Estimated useful life	5 years
Laboratory equipment \| Maximum
Property and equipment
Estimated useful life	7 years
Computer equipment and software
Property and equipment
Estimated useful life	3 years
Furniture and fixtures
Property and equipment
Estimated useful life	5 years
Office equipment
Property and equipment
Estimated useful life	5 years

Fair Value Measurements - Schedule of Company's Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Marketable securities	$ 44,066	$ 0
Fair Value, Measurements, Recurring
Assets:
Marketable securities	44,066
Total assets	62,930	89,713
Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Marketable securities	0
Total assets	14,864	89,713
Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Marketable securities	44,066
Total assets	48,067	0
Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Marketable securities	0
Total assets	0	0
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring
Assets:
Marketable securities	42,512
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Marketable securities	0
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Marketable securities	42,512
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Marketable securities	0
Corporate debt securities \| Fair Value, Measurements, Recurring
Assets:
Marketable securities	1,554
Corporate debt securities \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Marketable securities	0
Corporate debt securities \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Marketable securities	1,554
Corporate debt securities \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Marketable securities	0
Cash \| Fair Value, Measurements, Recurring
Assets:
Cash and cash equivalents	2,785
Cash \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	2,785
Cash \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0
Cash \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0
Money market funds \| Fair Value, Measurements, Recurring
Assets:
Cash and cash equivalents	9,647	89,713
Money market funds \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	9,647	89,713
Money market funds \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Money market funds \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0	$ 0
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring
Assets:
Cash and cash equivalents	4,000
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	0
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	4,001
U.S. government agency securities and treasuries \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents
Total cash and cash equivalents \| Fair Value, Measurements, Recurring
Assets:
Cash and cash equivalents	16,432
Total cash and cash equivalents \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	12,432
Total cash and cash equivalents \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	4,001
Total cash and cash equivalents \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	0
Restricted cash \| Fair Value, Measurements, Recurring
Assets:
Cash and cash equivalents	2,432
Restricted cash \| Fair Value, Measurements, Recurring \| Quoted prices in active markets (Level 1)
Assets:
Cash and cash equivalents	2,432
Restricted cash \| Fair Value, Measurements, Recurring \| Significant other observable inputs (Level 2)
Assets:
Cash and cash equivalents	0
Restricted cash \| Fair Value, Measurements, Recurring \| Significant unobservable inputs (Level 3)
Assets:
Cash and cash equivalents	$ 0

Marketable Securities (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 44,070,000
Unrealized Gains	4,000
Unrealized Losses	(8,000)
Fair Value	44,066,000
Available for sale securities held with maturities greater than one year	0	$ 0
U.S. government agency securities and treasuries
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	42,516,000
Unrealized Gains	4,000
Unrealized Losses	(8,000)
Fair Value	42,512,000
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,554,000
Unrealized Gains	0
Unrealized Losses	0
Fair Value	$ 1,554,000

Fair Value Measurements - Narrative (Details)	Dec. 31, 2016 USD ($)
Fair Value Disclosures [Abstract]
Available for sale securities in a continuous unrealized loss	$ 15,400,000
Available for sale securities continuous unrealized loss position	$ 7,700

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and equipment
Accumulated depreciation	$ (31)	$ (330)
Property and equipment, net	354	375
Depreciation and amortization	159	54	$ 35
Impairment charge	1,402
Machinery, computers and equipment
Property and equipment
Property and equipment, gross	385	687
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 0	$ 18

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accrued Expenses
Accrued restructuring	$ 1,609	$ 0
Professional fees	259	437
Clinical trial costs	220	489
Compensation and related items	154	1,151
Other	158	137
Total accrued expenses	2,400	$ 2,214
Severance and Benefits
Accrued Expenses
Accrued restructuring	1,097
Contract Termination Costs
Accrued Expenses
Accrued restructuring	$ 512

Shareholders’ Equity - Common Stock (Details)	12 Months Ended
Shareholders’ Equity - Common Stock (Details)	Dec. 31, 2016 vote
Equity [Abstract]
Number of votes per common stock	1

Shareholders’ Equity - Reverse Stock Split (Details)	1 Months Ended
Shareholders’ Equity - Reverse Stock Split (Details)	Sep. 30, 2015 $ / shares	Dec. 31, 2016 $ / shares	Dec. 31, 2015 $ / shares
Equity [Abstract]
Reverse stock split ratio	0.0667
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001

Shareholders’ Equity - Offerings (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		12 Months Ended
	Oct. 05, 2015	Oct. 31, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Common Stock
Class of Stock [Line Items]
Shares issued (in shares)					448
Common Stock \| Private Placement
Class of Stock [Line Items]
Shares issued (in shares)		2,395,010		2,395,010
Proceeds from issuance of common stock in private placement		$ 16.7
Common Stock \| Initial Public Offering
Class of Stock [Line Items]
Shares issued (in shares)		6,250,000		6,954,962
Share price (in dollars per share)		$ 7.00
Proceeds from issuance of common stock in initial public offering		$ 43.7
Common Stock \| Over-Allotment Option
Class of Stock [Line Items]
Shares issued (in shares)		704,962
CPRIT
Class of Stock [Line Items]
Grant award			$ 16.8
Shares of common stock to be purchased in private placement per the agreement			$ 16.8
CPRIT \| Common Stock \| Private Placement
Class of Stock [Line Items]
Shares issued (in shares)	2,395,010
Share price (in dollars per share)	$ 7.00
Proceeds from issuance of common stock in private placement	$ 16.6

Stock Option Plans - Plan Information (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 31, 2015	Dec. 31, 2008
ESPP
Stock Option Plans
Additional stock option and stock purchase rights available for grant (in shares)					369,960
Percentage of discount for employees under ESPP					15.00%
Purchase price as a percentage of fair value under ESPP					85.00%
Shares issued during the period under ESPP (in shares)					5,525
Stock Options
Stock Option Plans
Number of options outstanding (in shares)			354,833		1,905,214	1,529,459	500,911
Exercised intrinsic value					$ 13	$ 160	$ 383
Options exercisable, intrinsic value					28
Options outstanding, intrinsic value					28
Fair value of options vested					$ 1,524	$ 858	$ 198
2008 Plan
Stock Option Plans
Number of stock option and stock purchase rights available for grant (in shares)	1,061,585	669,935	554,782						330,582
Additional stock option and stock purchase rights available for grant (in shares)	391,650	115,153	224,200
Expiration period					10 years
Number of options outstanding (in shares)					706,656
Number of shares transferred (in shares)					(88,510)
2015 Plan
Stock Option Plans
Number of stock option and stock purchase rights available for grant (in shares)					2,801,836			1,671,800
Additional stock option and stock purchase rights available for grant (in shares)				1,041,526
Number of shares transferred (in shares)					88,510

Stock Option Plans - Schedule of Stock Option Activity (Details) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Shares
Outstanding at beginning of period (in shares)	1,529,459	500,911	354,833
Granted (in shares)	928,250	1,057,082	234,447
Exercised (in shares)	(5,313)	(28,516)	(80,816)
Forfeited/canceled (in shares)	(547,182)	(18)	(7,553)
Outstanding at end of period (in shares)	1,905,214	1,529,459	500,911	354,833
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 6.28	$ 4.95	$ 2.40
Granted (in dollars per share)	4.41	6.82	8.10
Exercised (in dollars per share)	1.65	2.36	2.40
Forfeited/canceled (in dollars per share)	6.26	7.50	4.70
Outstanding at end of period (in dollars per share)	$ 5.39	$ 6.28	$ 4.95	$ 2.40
Additional disclosures
Exercisable at end of period (in shares)	838,922
Exercisable at end of period (in dollars per share)	$ 5.45
Weighted Average Contractual Life (years)	7 years 5 months 27 days	9 years	8 years 10 months 6 days	8 years 9 months 18 days
Weighted Average Contractual Life (years), exercisable	5 years 6 months 26 days

Stock Option Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock-based compensation expense allocation
Stock-based compensation expense	$ 1,592	$ 985	$ 408
2015 Plan \| Stock Options
Stock-based compensation expense allocation
Unrecognized compensation cost	$ 3,500
Unrecognized compensation cost, period of recognition	2 years 7 months 21 days
2015 Plan \| Restricted Stock Units
Stock-based compensation expense allocation
Awards granted (in shares)	0
2015 Plan \| Stock Appreciation Rights
Stock-based compensation expense allocation
Awards granted (in shares)	0
Research and development expense
Stock-based compensation expense allocation
Stock-based compensation expense	$ 372	306	110
General and administrative expense
Stock-based compensation expense allocation
Stock-based compensation expense	$ 1,220	$ 679	$ 298

Stock option Plans - Fair value of stock options (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair value assumptions
Expected dividend yield	0.00%	0.00%	0.00%
Stock-based compensation, tax benefit	$ 0	$ 0	$ 0
Stock Options
Fair value assumptions
Risk free interest rate, minimum (as a percent)	1.10%	1.60%	1.80%
Risk free interest rate, maximum (as a percent)	1.60%	2.00%	2.80%
Expected volatility, minimum (as a percent)	76.90%	77.50%	75.30%
Expected volatility, maximum (as a percent)	79.50%	84.70%	85.40%
Weighted-average grant date fair value per share (in dollars per share)	$ 2.97	$ 4.73	$ 5.40
Stock Options \| Minimum
Fair value assumptions
Expected life (in years)	5 years 6 months	5 years 10 months 24 days	5 years 9 months 18 days
Stock Options \| Maximum
Fair value assumptions
Expected life (in years)	6 years 1 month 6 days	6 years 8 months 12 days	6 years 1 month 6 days

Restructuring Charges - Narrative (Details)	1 Months Ended	3 Months Ended				9 Months Ended	12 Months Ended
Restructuring Charges - Narrative (Details)	Feb. 28, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($) employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 28, 2016 employee
Restructuring Cost and Reserve [Line Items]
Number of employees \| employee									36
Restructuring expense		$ 4,442,000	$ 0	$ 0	$ 0		$ 3,040,000	$ 0
Asset impairment costs							1,402,000
Accrued restructuring		2,662,000					2,662,000	0
Accrued restructuring, current		1,609,000					1,609,000	$ 0
Accrued restructuring, long-term		1,100,000					1,100,000
Employee severance and benefit costs							1,500,000
Accrued redemption payments							100,000
Contract termination costs							1,486,000
Lab Equipment
Restructuring Cost and Reserve [Line Items]
Asset impairment costs							555,000
Salvage value		$ 320,000					320,000
Lab Equipment \| Subsequent Event
Restructuring Cost and Reserve [Line Items]
Sale of equipment	$ 325,000
Construction in Progress
Restructuring Cost and Reserve [Line Items]
Asset impairment costs							591,000
Furniture, Computers, Equipment and Leasehold Improvements
Restructuring Cost and Reserve [Line Items]
Asset impairment costs							$ 256,000
Scenario, Forecast
Restructuring Cost and Reserve [Line Items]
Number of employees \| employee						12
Restructuring expense						$ 4,700,000

Restructuring Charges - Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring and Related Activities [Abstract]
Employee severance and related costs	$ 1,554
Contract termination costs	1,486
Asset impairment costs	1,402
Total restructuring charges	$ 4,442	$ 0	$ 0

Restructuring Charges - Accumulated Restructuring Charges (Details) - USD ($)	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Balance at December 31, 2015				$ 0	$ 0
Restructuring Charge	$ 4,442,000	$ 0	$ 0	0	3,040,000	$ 0
Cash payments					(457,000)
Other					79,000
Balance at December 31, 2016	2,662,000				2,662,000	0
Employee severance and related costs
Restructuring Reserve [Roll Forward]
Balance at December 31, 2015				0	0
Restructuring Charge					1,554,000
Cash payments					(457,000)
Other					0
Balance at December 31, 2016	1,097,000				1,097,000	0
Contract Termination Costs
Restructuring Reserve [Roll Forward]
Balance at December 31, 2015				$ 0	0
Restructuring Charge					1,486,000
Cash payments					0
Other					79,000
Balance at December 31, 2016	$ 1,565,000				$ 1,565,000	$ 0

Income Taxes - Effective Income Tax Rate and Deferred Tax Assets and Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 0	$ 0	$ 0
Effective Income Tax Rate Reconciliation
Income tax benefit computed at federal statutory tax rate	(8,931,000)	(8,494,000)	(5,383,000)
Change in valuation allowance	9,287,000	9,002,000	5,675,000
General business credits	(572,000)	(661,000)	(386,000)
Other	216,000	153,000	94,000
Total	0	0	$ 0
Increase in valuation allowance	9,300,000
Components of Deferred Tax Assets and Liabilities
Net operating loss carryforwards	27,518,000	19,562,000
Depreciation and amortization	1,367,000	1,207,000
Stock‑based compensation	597,000	260,000
Credit carryforwards	1,717,000	1,147,000
Prepaid expenses	0	0
Accrued liabilities	538,000	264,000
Total deferred tax assets	31,737,000	22,440,000
Valuation allowance	(31,737,000)	(22,440,000)
Net deferred tax asset	$ 0	$ 0

Income Taxes - Net Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Federal
Net Operating Loss Carryforwards
Net operating loss carryforwards	$ 80.9	$ 57.5

Income Taxes - Tax Credits (Details) - Research and Development. - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tax Credits
Tax credit carryforwards	$ 1,441	$ 985
State
Tax Credits
Tax credit carryforwards	$ 267

Income Taxes - Other (Details) - USD ($)	12 Months Ended
Income Taxes - Other (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 0	$ 0
Interest and penalties related to income taxes	$ 0	$ 0

Shared Services Agreement with Asuragen (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shared Services Agreement with Asuragen
Related Party Transaction [Line Items]
Expense	$ 316	$ 490	$ 506
Sublease Agreement with Asuragen
Related Party Transaction [Line Items]
Expense	$ 59	$ 89

Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Retirement Plan (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Employee eligibility, period of service	90 days
Employer contributions	$ 169	$ 117	$ 91

License Agreements (Details) - USD ($)	1 Months Ended	12 Months Ended
License Agreements (Details) - USD ($)	Jan. 31, 2016	Dec. 31, 2016
Rosetta Genomics
License Agreements
Up-front and milestone payments	$ 1,600,000
Aggregate payments to be made for each licensed product upon achievement of certain development and regulatory milestones		$ 3,000,000
Marina Biotech
License Agreements
Up-front and milestone payments		2,100,000
Aggregate payments to be made for each licensed product upon achievement of certain development and regulatory milestones		6,000,000
Additional payments to be made for each licensed product upon achievement of certain development and regulatory milestones for a specified number of additional indications		4,000,000
Maximum cap on all milestone payments per product		10,000,000
Aggregate of all remaining development and regulatory milestone payments upon additional indications		4,000,000
Yale University
License Agreements
Maximum cap on all milestone payments per product		$ 600,000

Commitments and Contingencies (Detail)	1 Months Ended	12 Months Ended
Commitments and Contingencies (Detail)	Aug. 31, 2010 USD ($)	Dec. 31, 2016 USD ($) draw term	Jun. 30, 2016 USD ($)
Other Commitments [Line Items]
Initial term of lease		123 months
Number of terms lease can be extended \| term		2
Renewal term option of lease		60 months
Rent expense		$ 165,000
Annual base rent		$ 600,000
Rent free term		3 months
Yearly increases in base rent		3.00%
Tenant improvement allowance		$ 1,900,000
Additional tenant improvement allowance available		$ 1,300,000
Amortization period of additional improvement allowance		120 months
Number of draws taken on the additional improvement allowance \| draw		0
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2017		$ 450,929
2018		614,855
2019		633,364
2020		652,340
2021 and thereafter		4,565,888
Total		6,917,376
Proceeds from commercialization award grant	$ 10,300,000
Commercialization grant award, contract term	3 years
Standby Letters of Credit
Other Commitments [Line Items]
Standby letter of credit		2,400,000	$ 2,400,000.0
Reduced amount of standby letter of credit if certain conditions are met		$ 800,000

Net Loss Per Share Attributable to Common Stockholders - Computation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net loss	$ (8,694)	$ (5,365)	$ (5,638)	$ (6,571)	$ (8,789)	$ (6,231)	$ (5,684)	$ (4,279)	$ (26,268)	$ (24,983)	$ (15,834)
Accretion of convertible preferred stock to redemption value									0	(449)	0
Accrued dividends on convertible preferred stock									0	(3,871)	(2,824)
Net loss attributable to common stockholders					$ (8,890)	$ (7,785)	$ (7,229)	$ (5,397)	$ (26,268)	$ (29,303)	$ (18,658)
Weighted‑average number of common shares—basic and diluted (in shares)									20,833,963	5,010,323	64,131
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.42)	$ (0.26)	$ (0.27)	$ (0.32)	$ (0.45)	$ (82.16)	$ (78.87)	$ (60.99)	$ (1.26)	$ (5.85)	$ (291.00)

Net Loss Per Share Attributable to Common Stockholders - Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	1,905,214	9,450,949	6,100,850
Convertible preferred stock
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	0	7,921,490	5,599,939
Stock options
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	1,905,214	1,529,459	500,911

Selected Quarterly Data (unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
Selected Quarterly Data (unaudited) (Details) - USD ($)	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating expenses:
Research and development	$ 2,341,000	$ 3,384,000	$ 3,682,000	$ 4,523,000	$ 6,363,000	$ 4,683,000	$ 4,499,000	$ 3,402,000	$ 13,930,000	$ 18,947,000	$ 10,545,000
General and administrative	1,999,000	1,940,000	2,049,000	2,130,000	2,462,000	1,556,000	1,185,000	877,000	8,118,000	6,080,000	3,369,000
Restructuring Charge	4,442,000	0	0	0					3,040,000	0
Loss on disposal of assets	0	(128,000)							128,000	0	0
Total operating expenses	8,782,000	5,452,000	5,731,000	6,653,000	8,825,000	6,239,000	5,684,000	4,279,000	26,618,000	25,027,000	15,834,000
Other (income)	(88,000)	(87,000)	(93,000)	(82,000)	(36,000)	(8,000)	0	0
Net loss	$ (8,694,000)	$ (5,365,000)	$ (5,638,000)	$ (6,571,000)	(8,789,000)	(6,231,000)	(5,684,000)	(4,279,000)	(26,268,000)	(24,983,000)	(15,834,000)
Net loss attributable to common stockholders					$ (8,890,000)	$ (7,785,000)	$ (7,229,000)	$ (5,397,000)	$ (26,268,000)	$ (29,303,000)	$ (18,658,000)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.42)	$ (0.26)	$ (0.27)	$ (0.32)	$ (0.45)	$ (82.16)	$ (78.87)	$ (60.99)	$ (1.26)	$ (5.85)	$ (291.00)

Subsequent Events - Narrative (Details) $ in Thousands	1 Months Ended
Subsequent Events - Narrative (Details) $ in Thousands	Feb. 28, 2017 USD ($)
Lab Equipment \| Subsequent Event
Subsequent Event [Line Items]
Sale of equipment	$ 325