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Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
Document and Entity Information - USD ($) $ in Thousands	Dec. 31, 2015	Mar. 15, 2016	Jun. 30, 2015
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, 2015
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			$ 0
Common stock outstanding		20,830,555
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current Assets
Cash and cash equivalents	$ 89,713	$ 9,319
Grant reimbursement and other receivables	36	155
Prepaid expenses and other current assets	793	143
Total current assets	90,542	9,617
Property and equipment, net	375	116
Deferred offering costs		92
Total assets	90,917	9,825
Current liabilities:
Accounts payable	3,687	871
Accrued expenses	2,214	1,628
Total liabilities	5,901	2,499
Commitments and contingencies (Note 13)
Stockholders' Deficit:
Preferred stock, $0.001 par value, 5,000,000 and 0 shares authorized at December 31, 2015 and 2014; 0 shares outstanding at December 31, 2015 and 2014
Common stock, $0.001 par value; 250,000,000 shares authorized at December 31, 2015; 95,000,000 shares authorized at December 31, 2014; 20,830,555 shares issued and outstanding at December 31, 2015; 83,325 shares issued and outstanding at December 31, 2014	21
Additional paid in capital	161,518
Accumulated deficit	(76,523)	(47,951)
Total stockholders’ (equity) deficit	85,016	(47,951)
Total liabilities, convertible preferred stock and stockholders’ (equity) deficit	$ 90,917	9,825
Series A convertible preferred stock
Convertible preferred stock:
Convertible preferred stock		6,384
Series B convertible preferred stock
Convertible preferred stock:
Convertible preferred stock		1,500
Series B-1 convertible preferred stock
Convertible preferred stock:
Convertible preferred stock		7,498
Series C convertible preferred stock
Convertible preferred stock:
Convertible preferred stock		$ 39,895

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Convertible preferred stock, par value	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized	0	84,000,783
Convertible preferred stock, shares outstanding	0
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	95,000,000
Common stock, shares issued	20,830,555	83,325
Common stock, shares outstanding	20,830,555	83,325
Series A convertible preferred stock
Convertible preferred stock, shares authorized		3,192,083
Convertible preferred stock, shares issued	0	212,754
Convertible preferred stock, shares outstanding	0	212,754
Convertible preferred stock, liquidation preference	$ 0.0	$ 6.4
Series B convertible preferred stock
Convertible preferred stock, shares authorized		540,341
Convertible preferred stock, shares issued	0	36,019
Convertible preferred stock, shares outstanding	0	36,019
Convertible preferred stock, liquidation preference	$ 0.0	$ 1.5
Series B-1 convertible preferred stock
Convertible preferred stock, shares authorized		10,914,947
Convertible preferred stock, shares issued	0	727,643
Convertible preferred stock, shares outstanding	0	727,643
Convertible preferred stock, liquidation preference	$ 0.0	$ 7.5
Series C convertible preferred stock
Convertible preferred stock, shares authorized		69,353,712
Convertible preferred stock, shares issued	0	4,623,523
Convertible preferred stock, shares outstanding	0	4,623,523
Convertible preferred stock, liquidation preference	$ 0.0	$ 39.9
Series D convertible preferred stock
Convertible preferred stock, shares authorized		73,649,755
Convertible preferred stock, shares issued	0	0
Convertible preferred stock, shares outstanding	0	0

Condensed Statements of Operations - USD ($) $ in Thousands	12 Months Ended
Condensed Statements of Operations - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating expenses:
Research and development	$ 18,947	$ 10,545	$ 4,391
General and administrative	6,080	3,369	2,384
Write-off of offering costs		1,920
Total operating expenses	25,027	15,834	6,775
Other income:
Change in Fair Value of Option Liability			339
Interest income	44
Total other income	44		339
Net loss	(24,983)	(15,834)	(6,436)
Less: Accretion and dividends on convertible preferred stock	(4,320)	(2,824)	(2,324)
Net loss attributable to common stockholders	$ (29,303)	$ (18,658)	$ (8,760)
Net loss per share attributable to common stockholders - basic and diluted	$ (5.85)	$ (291.00)	$ (4,408.65)
Common shares used to compute basic and diluted net loss per share attributable to common stockholders	5,010,323	64,131	1,987

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock Initial Public Offering	Common Stock Private Placement	Common Stock	Additional Paid-in-Capital Initial Public Offering	Additional Paid-in-Capital Private Placement	Additional Paid-in-Capital	Accumulated Deficit	Initial Public Offering	Private Placement	Total
Balance at Dec. 31, 2012							$ (24,368)			$ (24,368)
Balance (in shares) at Dec. 31, 2012			1,835
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options						$ 1				1
Exercise of stock options (in shares)			226
Stock-based compensation						163				163
Reclassification of option liability						3,050				3,050
Accretion of convertible preferred stock						(831)				(831)
Series C dividends						(1,493)				(1,493)
Net loss							(6,436)			(6,436)
Balance at Dec. 31, 2013						890	(30,804)			(29,914)
Balance (in shares) at Dec. 31, 2013			2,061
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options						209				209
Exercise of stock options (in shares)			80,816
Issuance of common stock						4				4
Issuance of common stock (in shares)			448
Stock-based compensation						408				408
Series C dividends						(1,511)	(1,313)			(2,824)
Net loss							(15,834)			(15,834)
Balance at Dec. 31, 2014							(47,951)			$ (47,951)
Balance (in shares) at Dec. 31, 2014			83,325							83,325
Increase (Decrease) in Stockholders' Equity (Deficit)
Exercise of stock options			$ 1			66				$ 67
Exercise of stock options (in shares)			28,516
Stock-based compensation						985				985
Accretion of convertible preferred stock						(180)	(269)			(449)
Series C and Series D dividends						(551)	(3,320)			(3,871)
Conversion of preferred shares			$ 11			100,927				100,938
Conversion of preferred shares (in shares)			11,368,742
Initial public offerings of common stock, net of offering expenses of $5,170	$ 7	$ 2		$ 43,657	$ 16,614			$ 43,664	$ 16,616
Initial public offerings of common stock, net of offering expenses of $5,170 (in shares)	6,954,962	2,395,010
Net loss							(24,983)			(24,983)
Balance at Dec. 31, 2015			$ 21			$ 161,518	$ (76,523)			$ 85,016
Balance (in shares) at Dec. 31, 2015			20,830,555							20,830,555

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

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (24,983)	$ (15,834)	$ (6,436)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	54	35	36
Stock-based compensation	985	408	163
Issuance of stock for services		4
Change in fair value of option liability			(339)
Changes in operating assets and liabilities:
Grant reimbursement and other receivables	119	40	121
Prepaid expenses and other current assets	(650)	(99)	2
Deferred offering costs		105	(197)
Other noncurrent assets		17	(17)
Accounts payable	2,816	189	(132)
Accrued expenses	524	1,165	303
Net cash used in operating activities	(21,135)	(13,970)	(6,496)
Investing activities
Purchases of property and equipment	(251)	(102)	(7)
Net cash used in investing activities	(251)	(102)	(7)
Financing activities
Proceeds from issuance of convertible preferred stock, net of issuance costs	41,433		16,418
Proceeds from the issuance of common stock, net of issuance costs	60,280
Proceeds from exercise of stock options	67	209	1
Cash provided by financing activities	101,780	209	16,419
Net increase (decrease) in cash and cash equivalents	80,394	(13,863)	9,916
Cash and cash equivalents at beginning of period	9,319	23,182	13,266
Cash and cash equivalents at end of period	89,713	$ 9,319	$ 23,182
Supplemental schedule of noncash investing activities
Conversion of preferred stock to common stock	$ 100,938

Organization	12 Months Ended
Organization	Dec. 31, 2015
Organization
Organization	MIRNA THERAPEUTICS, INC. Notes to Financial Statements 1. Organization Mirna Therapeutics, Inc. (“Mirna” or “the Company”) is a clinical stage biopharmaceutical company developing a broad pipeline of 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. The Company is located in Austin, Texas. In connection with the completion of its initial public offering (“IPO”), on October 6, 2015, the Company filed an amended and restated certificate of incorporation and bylaws, which, among other things, authorizes 250,000,000 shares of common stock and 5,000,000 shares of preferred stock.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Summarty of Significant Accounting Policies

Summary of Significant Accounting Policies

2. 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.

Liquidity

The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are the 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’s ability to fund its planned clinical operations, including completion of its planned trials, is expected to depend on the amount and timing of cash receipts from future collaboration or product sales and/or financing transactions. The Company believes that its cash and cash equivalents of $89.7 million at December 31, 2015, will enable the Company to maintain its current and planned operations for the next twelve months.

Research and development costs

Research and development costs consist of costs we incur for our 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

The Company estimates pre-clinical study and clinical trial expenses pursuant to contracts with research institutions and contract research organizations that conduct and manage preclinical studies and clinical trials on the Company’s behalf based on estimates of the level of service performed and the underlying agreement. Further, the Company accrues expenses related to clinical trials based on the level of patient enrollment and other activities according to the related agreements. The Company monitors patient enrollment levels and other activities to the extent reasonably possible and adjusts estimates accordingly.

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, 2015 and 2014, the Company does not have any significant uncertain tax positions.

Comprehensive loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions, and other events and circumstances from non‑owner sources. The Company had no items of other comprehensive loss for the years ended December 31, 2015, 2014 and 2013.

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 money market funds, 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. The Company holds these investments in highly‑rated financial institutions, 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.

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 following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2015:


	Level 1		Level 2		Level 3		Total
Money market funds	$	89,713	$	—	$	—	$	89,713
Total	$	89,713	$	—	$	—	$	89,713

The following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2014 (in thousands):


	Level 1		Level 2		Level 3		Total
Money market funds	$	9,319	$	—	$	—	$	9,139
Total	$	9,319	$	—	$	—	$	9,139

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, 2015 and 2014, due to their short‑term nature.

There have been no changes to the valuation methods during the years ended December 31, 2015 and 2014. 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, 2015 or 2014.

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 has not recognized any impairment charges through December 31, 2015.

Deferred 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.

Convertible preferred stock

Prior to the Company’s IPO, the Company initially recorded convertible preferred stock that could have been redeemed at the option of the holder or based upon the occurrence of events not under the Company’s control outside of stockholders’ deficit at the value of the proceeds received, net of issuance costs. Subsequently, the Company adjusted the carrying value to the redemption value at each reporting period. In the absence of retained earnings, these accretion charges were recorded against additional paid‑in capital, if any, and then to accumulated deficit. Upon completing the IPO, all shares of the Company’s convertible preferred stock then outstanding was converted into shares of our common stock.

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, 2015, 2014, and 2013, 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 February 2016, the Financial Accounting Standards Board (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. We are currently evaluating our expected adoption method and the impact of this new standard on our financial statements.

In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). The standard requires all deferred income tax assets and liabilities to be classified as noncurrent within an entity’s consolidated balance sheet. ASU 2015-17 is effective for annual periods beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. Entities are also permitted to apply the revised guidance on either a prospective or retrospective basis. The Company early adopted this guidance on a prospective basis and has classified deferred income taxes in the consolidated balance sheets as noncurrent beginning with the period ended December 31, 2015. Adoption of this guidance did not affect the historical consolidated results of operations, financial position or liquidity.

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. We will adopt this standard in 2016.

Cancer Prevention and Research Institute of Texas Grant and Other Grants	12 Months Ended
	Dec. 31, 2015
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Cancer Prevention and Research Institute of Texas Grant and Other Grants	3. Cancer Prevention and Research Institute of Texas Grant and Other Grants In August 2010, the Company received a $10.3 million commercialization award from the State of Texas through the Cancer Prevention and Research Institute of Texas (“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. The commercialization award was a reimbursement grant and was terminated on January 31, 2014. The Company is obligated to make certain payments to CPRIT that survive termination. Under the terms of the award, the Company is required to pay to CPRIT a portion of its revenues from sales of certain products by the Company, or received from the Company’s 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. At such time when the Company records revenues that are subject to royalties owed to CPRIT, the Company will record such royalties as cost of revenues in the period in which the related revenue is recorded. If the Company exercises its right to make a one‑time payment to CPRIT to buy out the royalty payment obligations, the Company will record the entire one‑time payment as cost of revenues in the period in which it exercises such right. In September 2015, the Company entered into a new grant contract with CPRIT in connection with an award of approximately $16.8 million. This 2015 award has a three‑year term, subject to extension by mutual agreement by the Company and CPRIT. However, in contrast to the Company’s 2010 award, this 2015 award does not include any royalty obligation upon commercialization of the Company’s product candidates, nor is the Company required to repay the grant proceeds under specified circumstances. Instead, the 2015 award is 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 an initial public offering, subject to certain conditions, occurring prior to December 31, 2016, at the public offering price. The private placement was completed in October 2015 with the issuance of 2,395,010 shares of the common stock at $7.00 per share. Pursuant to the grant contract, the Company will conduct preclinical and clinical development of certain combination therapy approaches for lung or liver cancer involving the Company’s lead product candidate, MRX34. If, at any time during the term of the grant contract and following the consummation of our initial public offering, the Company determines that the project provided for by the grant contract is no longer commercially feasible for it, then the Company and CPRIT are required to consult in order to reallocate the remaining unspent budget for the project to another oncology project in our product candidate pipeline. Total government grants recognized as a reduction of research and development expenses during the years ended December 31, 2015, 2014, and 2013 were $458,000; $81,000 and $3,850,000, respectively.

Property and Equipment

12 Months Ended

Dec. 31, 2015

Property and Equipment

Property and Equipment

4. Property and Equipment

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


	December 31,		December 31,
	2015		2014

Machinery, computers and equipment	$	687	$	373
Leasehold improvements		18		18
Accumulated depreciation		(330)		(275)
	$	375	$	116

Depreciation expense was $54,000, $35,000 and $36,000 in 2015, 2014 and 2013, respectively.

Accrued Expenses

12 Months Ended

Dec. 31, 2015

Accrued Expenses

Accrued Expenses

5. Accrued expenses

Accrued expenses consist of the following (in thousands):


	December 31,
	2015		2014

Compensation and related items	$	1,151	$	243
Professional fees		437		210
Clinical trial costs		489		551
Drug product costs		—		525
State franchise taxes		106		—
Other		31		99
	$	2,214	$	1,628

Convertible Preferred Stock

12 Months Ended

Dec. 31, 2015

Convertible Preferred Stock.

Convertible Preferred Stock

6. Convertible Preferred Stock

On various dates between March 31, 2015 and April 20, 2015, the Company completed two closings of an offering of the Company’s Series D convertible preferred stock (“Series D”). The Company issued 4,559,675 shares with gross proceeds totaling approximately $41.8 million.

In conjunction with the IPO, the Company’s Series A, Series B, Series B-1, Series C and Series D preferred stock was converted into an aggregate of 10,159,614 shares of the Company’s common stock on a 1-for-1 basis. In addition and in conjunction with the IPO, cumulative dividends on the Company’s Series C and Series D preferred stock, which totaled approximately $8.5 million, were paid in-kind, with a total of 1,209,128 shares of common stock issued to shareholders, which were calculated by dividing the cumulative dividends earned by the offering price per share of $7.00 in the IPO.

As of December 31, 2015, the Company had no outstanding convertible preferred stock.

Conversion

Prior to the IPO, the Series A, Series B, Series B‑1, Series C and Series D were convertible into common stock at any time at the option of the holders. The conversion price was initially set at the original issue price per share of the convertible preferred stock and was adjusted to prevent dilution for stock splits, combinations and dividends.

The Company’s convertible preferred stock would automatically convert into shares of common stock at the then‑applicable conversion price for each such series, immediately upon the closing of a firm underwritten public offering pursuant to an effective registration statement under the Securities Act of 1933, with minimum offering requirements. The Company’s convertible preferred stock would also automatically convert upon an affirmative vote of at least a majority of the convertible preferred stockholders voting together as a single class on an as‑if converted basis.

Voting

Prior to the IPO, holders of the Company’s convertible preferred stock were entitled to voting rights equal to holders of common stock. Holders of the Company’s convertible preferred stock were also entitled to vote on certain matters with all shares of convertible preferred stock voting as a single class. Holders of the Company’s Series D convertible preferred stock were also entitled to vote on certain matters with all Series D shares voting as a single class.

Dividends

Prior to the IPO and subject to certain circumstances, holders of shares of Series C and shares of Series D were entitled to receive cumulative dividends at a rate per annum of 8%, payable in cash or in kind at the option of the holder of the stock. Such dividends were payable in cash or in‑kind in the event of a liquidation, redemption or conversion. In the event of a conversion of the Series C shares and the Series D shares in connection with an initial public offering the cumulative dividends were only payable in‑kind.

Liquidation

Prior to the IPO, in the event of any liquidation, dissolution or winding up of the affairs of the Company, merger or sale resulting in a change of control, or sale or license of all assets, the holders of the then-outstanding shares would receive an amount per share equal to the sum of $9.165, $7.635, $10.305, $31.59 and $19.95 per share of Series D, Series C, Series B-1, Series B and Series A, respectively, plus all accrued and/or declared but unpaid dividends, payable in preference and priority to any payments made to the holders of the then-outstanding preferred or common stock. In the event that the Series B-1 has been deemed converted to common stock prior to the liquidation amounts being paid to Series A or Series B holders, the amount per share to be received by the holders of the Series B and Series A would be adjusted to $41.64 and $30.00 per share, respectively.

Redemption

Prior to the IPO, at any time after March 27, 2019, with a written request from at least sixty percent of the holders of the then-outstanding Series D, the Company would redeem the requested shares of the Series D at an amount equal to the original issue price, plus any accrued and/or declared but unpaid dividends, where the original purchase price is $9.165.

Prior to the IPO, at any time after October 22, 2017, with a written request from the majority holders of the then-outstanding Series C, the Company would redeem the requested shares of the Series C at an amount equal to the original issue price, plus any accrued and/or declared but unpaid dividends, where the original purchase price is $7.635.

The Series A and Series B were not entitled to any redemption rights. However, because a majority of the Company's outstanding stock is in the control of the convertible preferred stockholders who also control the Company's board of directors, a hostile takeover or other sale could have occurred outside the Company's control and thereby trigger a "deemed liquidation" and payment of liquidation preferences. Accordingly, the Company classified convertible preferred stock outside of stockholders' deficit for all periods presented.

The Company adjusted the carrying value of the convertible preferred stock to the liquidation preferences of such shares at each reporting period end prior to the IPO. The change in carrying value of the convertible preferred stock was recorded as a charge to additional paid-capital, if any, and then to accumulated deficit.

Conversion of Preferred Stock and Accrued Dividends

Immediately prior to the closing of the IPO, each share of the Company’s outstanding preferred stock was converted into one share of common stock. In conjunction with the conversion, cumulative dividends on the Company’s Series C and Series D preferred stock were paid with in-kind in shares of common stock. The following table presents the conversion of preferred stock and accrued dividends paid in-kind into common stock on October 5, 2015:


	Prior to Conversion
	Preferred Shares	Paid-in-Kind Dividend Shares	Subsequent to Conversion
Convertible preferred stock
Series A	212,754		—
Series B	36,019		—
Series B-1	727,643		—
Series C	4,623,523	964,667	—
Series D	4,559,675	244,461
Total	10,159,614	1,209,128

Common stock	—	—	11,368,742

Shareholder’s Equity	12 Months Ended
Shareholder’s Equity	Dec. 31, 2015
Shareholder’s Equity
Shareholder’s Equity	7. 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, 2015, 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”), as discussed in Note 3, in connection with an award of approximately $16.8 million. The 2015 award is 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 option 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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-Paragraph 4
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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Reference 7: http://www.xbrl.org/2003/role/presentationRef
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Reference 8: http://www.xbrl.org/2003/role/presentationRef
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-Subparagraph (SX 210.3-04)
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 505
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

+ Details

Stock Option Plans

12 Months Ended

Dec. 31, 2015

Stock Option Plans

Stock Option Plans

8. 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 800,478 options outstanding in the 2008 Plan at December 31, 2015 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. Under the 2015 Plan, 1,671,800 shares of the Company’s common stock will be initially authorized and reserved for issuance, and will be added to the outstanding shares transferred from the 2008 Plan for a total of 2,472,278 authorized for grant under the 2015 Plan at December 31, 2015.

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. There were no sales under the ESPP as of December 31, 2015. Shares available for future purchase under the ESPP were 167,180 at December 31, 2015.

Stock Option Activity

The Company’s stock option activity for the years ended December 31, 2015, 2014, and 2013 was as follows:


		Weighted‑
		Average		Weighted‑Average
	Number	Exercise		Contractual
	of Shares	Price		Life (years)
Outstanding at December 31, 2012	31,712	$	7.50	5.84
Granted	329,323		1.95
Exercised	(226)		2.40
Forfeited/canceled	(5,976)		3.50
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)		4.7
Outstanding at December 31, 2014	500,911		4.95	8.52
Granted	1,057,082		6.82
Exercised	(28,516)		2.36
Forfeited/canceled	(18)		7.50
Outstanding at December 31, 2015	1,529,459	$	6.29	9.00
Options exercisable at December 31, 2015	356,661	$	4.56	7.61

The total intrinsic value of options exercised during the years ended December 31, 2015, 2014 and 2013 was $160,000, $383,000, and $440,000, respectively. The intrinsic value of options exercisable and total options outstanding at December 31, 2015 was $820,000 and $985,000, respectively. The total fair value of options vested during the years ended December 31, 2015, 2014 and 2013 was $858,000, $198,000 and $132,000, respectively.

Stock Based Compensation Expense

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


	Year Ended
	December 31,
	2015		2014		2013

Research and development expense	$	306	$	110	$	55
General and administrative expense		679		298		108
	$	985	$	408	$	163

There was approximately $5.2 million of unrecognized compensation cost related to the stock options granted under the 2015 Plan, which is expected to be amortized over the next 3.8 years. There were no restricted stock units or stock appreciation rights granted under the 2015 Plans of December 31, 2015.

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, 2015, 2014 and 2013 are as follows:


	Year Ended December 31,
	2015		2014		2013

Expected life (in years)		5.9 - 6.7		5.8 - 6.1		5.6 - 6.1
Risk‑free interest rate		1.54% - 1.98%		1.8% - 2.8%		0.9% - 2.0%
Expected volatility		77.5% - 84.7%		75.3% - 85.4%		74.7% - 76.2%
Expected dividend yield		—		—		—
Weighted-average grant date fair value per share	$	4.73	$	5.40	$	1.95

No related tax benefits were recognized for the years ended December 31, 2015, 2014 or 2013.

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Taxes

Income Taxes

9. Income Taxes

The Company recorded no provision for income taxes as of December 31, 2015 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, 2015, 2014 and 2013 (in thousands):


	2015		2014		2013

Income tax benefit computed at federal statutory tax rate	$	(8,494)	$	(5,383)	$	(2,188)
Change in valuation allowance		9,002		5,675		2,264
General business credits		(661)		(386)		(32)
Change in fair value of option liability		—		—		(115)
Other		153		94		71
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, 2015, the valuation allowance increased by $9.0 million. Significant components of the Company’s deferred tax assets and liabilities as of December 31, 2015 and 2014 are as follows (in thousands):


	2015		2014

Net operating loss carryforwards	$	19,562	$	12,414
Depreciation and amortization		1,207		507
Stock‑based compensation		260		71
Credit carryforwards		1,147		444
Prepaid expenses		—		(49)
Accrued liabilities		264		30
Total deferred tax assets		22,440		13,417
Valuation allowance		(22,440)		(13,417)
Net deferred tax asset	$	—	$	—

As of December 31, 2015 and 2014, the Company had net operating loss (“NOL”) carryforwards for federal income tax purposes of approximately $57.5 million and $36.5 million, respectively. As of December 31, 2015 and 2014, the Company also had available research and development tax credits for federal income tax purposes of approximately $985,000 and $405,000, respectively. If not utilized, these carryforwards expire at various dates beginning in 2028. As of December 31, 2015, the Company had state research and development tax credit carryforwards of approximately $162,000, 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, 2015. 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, 2015 and 2014, the Company had no unrecognized tax benefits. During the years ended December 31, 2015 and 2014, 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, 2015, the statute of limitations for assessment by the Internal Revenue Service (“IRS”) is open for the 2012 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 2011 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, 2015
Shared Services Agreement with Asuragen
Shared Services Agreement with Asuragen	10. 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 $490,000, $506,000 and $908,000 for the years ended December 31, 2015, 2014 and 2013, 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 $89,000 and $15,000 for the year ended December 31, 2015 and 2014, respectively. Both the lease and the shared service agreements expire on August 31, 2016, with the ability by either party to terminate with six months’ notice.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Retirement Plan	12 Months Ended
Retirement Plan	Dec. 31, 2015
Retirement Plan
Retirement Plan	11. 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 2015, 2014 and 2013 were approximately $117,000, $91,000 and $64,000, respectively.

License Agreements	12 Months Ended
License Agreements	Dec. 31, 2015
License Agreements
License agreements	12. 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 lead product candidate and non-exclusive for products that are not related. Under the License Agreement, the Company paid Rosetta an up-front, non- refundable payment of $1.6 million in January 2016. 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 lead therapeutic product, MRX34. 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, 2015 in up‑front and milestone payments and as consideration for the inclusion within the license of four additional microRNA compounds. As the Company progresses with respect to development and commercialization of its products, the Company will 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 lead 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 lead 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.

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2015
Commitments and Contingencies.
Commitments and Contingencies	13. Commitments and Contingencies Shared Services Agreement Pursuant to a shared services agreement and sublease with Asuragen, the Company has remaining commitments for payments in 2016 of approximately $381,000 for shares services and rent under the Shared Services Agreement and Sublease Agreement with Asuragen. (see Note 10) 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, 2015

Net Loss Per Share Attributable to Common Stockholders

Net Loss Per Share Attributable to Common Stockholders

14. 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,
	2015		2014		2013

Net loss	$	(24,983)	$	(15,834)	$	(6,436)
Accretion of convertible preferred stock to redemption value		(449)		—		(831)
Accrued dividends on convertible preferred stock		(3,871)		(2,824)		(1,493)
Net loss attributable to common stockholders—basic and diluted		(29,303)		(18,658)		(8,760)
Weighted-average number of common shares—basic and diluted		5,010,323		64,131		1,987
Net loss per share attributable to common stockholders—basic and diluted	$	(5.85)	$	(291.00)	$	(4,408.65)

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,
	2015	2014	2013

Convertible preferred stock	7,921,490	5,599,939	5,599,939
Stock options	1,529,459	500,911	354,834
	9,450,949	6,100,850	5,954,773

Selected Quarterly Data (unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Information [Text Block]

15. Selected Quarterly Data (unaudited)

The following table contains quarterly financial information for 2015 and 2014. The operating results for any quarter are not necessary indicative of results for any future period.


	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)


	2014 Quarter Ended
	December 31		September 30		June 30		March 31

Operating Expenses:
Research and Development	$	3,501	$	2,788	$	2,068	$	2,188
General and Administrative		877		715		929		848
Write-off of offering costs		—		1,920		—		—
Total operating expenses		4,378		5,423		2,997		3,036
Other (income)		—		—		—		—
Net loss		(4,378)		(5,423)		(2,997)		(3,036)
Net loss attributable to common stockholders		(5,090)		(6,135)		(3,701)		(3,732)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Summarty of Significant Accounting Policies

Use of estimates

Liquidity

Research and development costs

Stock-based compensation

Stock‑based compensation

Clinical Trial and Pre-Clinical Study Accruals

Income taxes

Income Taxes

Comprehensive loss

Cash and cash equivalents

Concentrations of credit risk

Fair value measurements

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

The following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2015:


	Level 1		Level 2		Level 3		Total
Money market funds	$	89,713	$	—	$	—	$	89,713
Total	$	89,713	$	—	$	—	$	89,713

The following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2014 (in thousands):


	Level 1		Level 2		Level 3		Total
Money market funds	$	9,319	$	—	$	—	$	9,139
Total	$	9,319	$	—	$	—	$	9,139

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

Deferred offering costs

Segment and geographic information

Convertible preferred stock

Net loss per share attributable to common stockholders

Recent accounting pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Summarty of Significant Accounting Policies

Schedule of money market funds measured at fair value on a recurring basis

The following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2015:


	Level 1		Level 2		Level 3		Total
Money market funds	$	89,713	$	—	$	—	$	89,713
Total	$	89,713	$	—	$	—	$	89,713

The following table summarizes the money market funds measured at fair value on a recurring basis as of December 31, 2014 (in thousands):


	Level 1		Level 2		Level 3		Total
Money market funds	$	9,319	$	—	$	—	$	9,139
Total	$	9,319	$	—	$	—	$	9,139

Schedule of useful life of 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

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property and Equipment

Schedule of property and equipment

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


	December 31,		December 31,
	2015		2014

Machinery, computers and equipment	$	687	$	373
Leasehold improvements		18		18
Accumulated depreciation		(330)		(275)
	$	375	$	116

Accrued Expenses (Tables)

12 Months Ended

Dec. 31, 2015

Accrued Expenses

Schedule of accrued expenses

Accrued expenses consist of the following (in thousands):


	December 31,
	2015		2014

Compensation and related items	$	1,151	$	243
Professional fees		437		210
Clinical trial costs		489		551
Drug product costs		—		525
State franchise taxes		106		—
Other		31		99
	$	2,214	$	1,628

Convertible Preferred Stock (Tables)

12 Months Ended

Dec. 31, 2015

Shareholder’s Equity

Schedule of Conversion of preferred stock and accrued dividends paid in kind into common stock

The following table presents the conversion of preferred stock and accrued dividends paid in-kind into common stock on October 5, 2015:


	Prior to Conversion
	Preferred Shares	Paid-in-Kind Dividend Shares	Subsequent to Conversion
Convertible preferred stock
Series A	212,754		—
Series B	36,019		—
Series B-1	727,643		—
Series C	4,623,523	964,667	—
Series D	4,559,675	244,461
Total	10,159,614	1,209,128

Common stock	—	—	11,368,742

Stock Option Plans (Tables)

12 Months Ended

Dec. 31, 2015

Stock Option Plans

Schedule of stock option activity


		Weighted‑
		Average		Weighted‑Average
	Number	Exercise		Contractual
	of Shares	Price		Life (years)
Outstanding at December 31, 2012	31,712	$	7.50	5.84
Granted	329,323		1.95
Exercised	(226)		2.40
Forfeited/canceled	(5,976)		3.50
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)		4.7
Outstanding at December 31, 2014	500,911		4.95	8.52
Granted	1,057,082		6.82
Exercised	(28,516)		2.36
Forfeited/canceled	(18)		7.50
Outstanding at December 31, 2015	1,529,459	$	6.29	9.00
Options exercisable at December 31, 2015	356,661	$	4.56	7.61

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,
	2015		2014		2013

Research and development expense	$	306	$	110	$	55
General and administrative expense		679		298		108
	$	985	$	408	$	163

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


	Year Ended December 31,
	2015		2014		2013

Expected life (in years)		5.9 - 6.7		5.8 - 6.1		5.6 - 6.1
Risk‑free interest rate		1.54% - 1.98%		1.8% - 2.8%		0.9% - 2.0%
Expected volatility		77.5% - 84.7%		75.3% - 85.4%		74.7% - 76.2%
Expected dividend yield		—		—		—
Weighted-average grant date fair value per share	$	4.73	$	5.40	$	1.95

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Taxes

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


	2015		2014		2013

Income tax benefit computed at federal statutory tax rate	$	(8,494)	$	(5,383)	$	(2,188)
Change in valuation allowance		9,002		5,675		2,264
General business credits		(661)		(386)		(32)
Change in fair value of option liability		—		—		(115)
Other		153		94		71
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, 2015 and 2014 are as follows (in thousands):


	2015		2014

Net operating loss carryforwards	$	19,562	$	12,414
Depreciation and amortization		1,207		507
Stock‑based compensation		260		71
Credit carryforwards		1,147		444
Prepaid expenses		—		(49)
Accrued liabilities		264		30
Total deferred tax assets		22,440		13,417
Valuation allowance		(22,440)		(13,417)
Net deferred tax asset	$	—	$	—

Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2015

Net Loss Per Share Attributable to Common Stockholders

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,
	2015		2014		2013

Net loss	$	(24,983)	$	(15,834)	$	(6,436)
Accretion of convertible preferred stock to redemption value		(449)		—		(831)
Accrued dividends on convertible preferred stock		(3,871)		(2,824)		(1,493)
Net loss attributable to common stockholders—basic and diluted		(29,303)		(18,658)		(8,760)
Weighted-average number of common shares—basic and diluted		5,010,323		64,131		1,987
Net loss per share attributable to common stockholders—basic and diluted	$	(5.85)	$	(291.00)	$	(4,408.65)

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


	December 31,
	2015	2014	2013

Convertible preferred stock	7,921,490	5,599,939	5,599,939
Stock options	1,529,459	500,911	354,834
	9,450,949	6,100,850	5,954,773

Selected Quarterly Data (unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Data (unaudited)


	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)


	2014 Quarter Ended
	December 31		September 30		June 30		March 31

Operating Expenses:
Research and Development	$	3,501	$	2,788	$	2,068	$	2,188
General and Administrative		877		715		929		848
Write-off of offering costs		—		1,920		—		—
Total operating expenses		4,378		5,423		2,997		3,036
Other (income)		—		—		—		—
Net loss		(4,378)		(5,423)		(2,997)		(3,036)
Net loss attributable to common stockholders		(5,090)		(6,135)		(3,701)		(3,732)

Organization (Details) - shares	Dec. 31, 2015	Oct. 06, 2015	Dec. 31, 2014
Organization
Common stock, shares authorized	250,000,000	250,000,000	95,000,000
Preferred stock, shares authorized	5,000,000	5,000,000	0

Summary of Significant Accounting Policies - Liquidity (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Summarty of Significant Accounting Policies
Cash and cash equivalents	$ 89,713	$ 9,319	$ 23,182	$ 13,266

Summary of Significant Accounting Policies - Fair value measurements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair value of assets measured at fair value on a recurring basis
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
Recurring
Fair value of assets measured at fair value on a recurring basis
Total	89,713,000	9,139,000
Recurring \| Money Market Funds
Fair value of assets measured at fair value on a recurring basis
Money market funds	89,713,000	9,139,000
Recurring \| Level 1
Fair value of assets measured at fair value on a recurring basis
Total	89,713,000	9,319,000
Recurring \| Level 1 \| Money Market Funds
Fair value of assets measured at fair value on a recurring basis
Money market funds	$ 89,713,000	$ 9,319,000

Summary of Significant Accounting Policies - Property and equipment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)
Property and equipment
Impairment of long-lived assets	$ 0
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

Summary of Significant Accounting Policies - Other (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 segment	Dec. 31, 2014 USD ($)
Summarty of Significant Accounting Policies
Deferred offering costs expensed \| $		$ 1,920
Number of operating segments	1
Number of geographic segments	1

Cancer Prevention and Research Institute of Texas Grant and Other Grants (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended			12 Months Ended
	Oct. 05, 2015	Oct. 31, 2015	Sep. 30, 2015	Aug. 31, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Grant proceeds recognized as a reduction of research and development expense					$ 458	$ 81	$ 3,850
Private Placement \| Common Stock
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Shares issued (in shares)					2,395,010
CPRIT
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Commercialization award received				$ 10,300
Grant award			$ 16,800
Award term			3 years
Shares of common stock to be purchased in private placement per the agreement			$ 16,800
CPRIT \| Maximum
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Payment to CPRIT (in percentage)				1.00%
CPRIT \| Private Placement \| Common Stock
Cancer Prevention and Research Institute of Texas Grant and Other Grants
Shares issued (in shares)	2,395,010	2,395,010
Share price (in dollars per share)	$ 7.00	$ 7.00

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property and equipment
Less accumulated depreciation and amortization	$ (330)	$ (275)
Property and equipment, net	375	116
Depreciation and amortization	54	35	$ 36
Machinery, computers and equipment
Property and equipment
Property and equipment, gross	687	373
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 18	$ 18

Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accrued Expenses
Compensation and related items	$ 1,151	$ 243
Professional fees	437	210
Clinical trial costs	489	551
Drug Product Costs		525
State franchise taxes	106
Other	31	99
Total accrued expenses	$ 2,214	$ 1,628

Convertible Preferred Stock - Information (Details) $ / shares in Units, $ in Thousands		1 Months Ended	9 Months Ended	12 Months Ended
	Oct. 06, 2015 USD ($) $ / shares shares	Apr. 20, 2015 USD ($) item shares	Sep. 30, 2015 $ / shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2013 USD ($)	Oct. 31, 2015 $ / shares	Dec. 31, 2014 shares
Proceeds from the issuance of convertible preferred stock \| $				$ 41,433	$ 16,418
Convertible preferred stock (in shares) \| shares				0
Conversion of preferred shares \| $				$ 100,938
Series A convertible preferred stock
Convertible preferred stock (in shares) \| shares				0			212,754
Liquidation preference (in dollars per share)			$ 19.950
Adjusted Liquidated preference			30.00
Series B convertible preferred stock
Convertible preferred stock (in shares) \| shares				0			36,019
Liquidation preference (in dollars per share)			31.590
Adjusted Liquidated preference			41.64
Series B-1 convertible preferred stock
Convertible preferred stock (in shares) \| shares				0			727,643
Liquidation preference (in dollars per share)			10.305
Series C convertible preferred stock
Convertible preferred stock (in shares) \| shares				0			4,623,523
Liquidation preference (in dollars per share)			7.635
Original purchase price			7.635
Series D convertible preferred stock
Number of offerings closed \| item		2
Convertible preferred stock issued (in shares) \| shares		4,559,675
Proceeds from the issuance of convertible preferred stock \| $		$ 41,800
Convertible preferred stock (in shares) \| shares				0			0
Liquidation preference (in dollars per share)			$ 9.165
Minimum Percentage of request from holders			60.00%
Original purchase price			$ 9.165
Series C and Series D Preferred Stock
Cumulative dividends \| $	$ 8,500
Dividend rate (as a percent)			8.00%
Common Stock
Conversion of preferred stock into common stock (in shares) \| shares	10,159,614
Conversion ratio	1
Common shares issued in lieu of cumulative dividends on Series C and Series D preferred stock (in shares) \| shares	1,209,128
Conversion of preferred shares \| $				$ 11
Common Stock \| Initial Public Offering
Share price (in dollars per share)	$ 7.00					$ 7.00

Convertible Preferred Stock - Conversion (Details) - shares	Oct. 06, 2015	Oct. 05, 2015
Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		10,159,614
Paid-in-Kind Dividend Shares		1,209,128
Common Stock
Conversion of Preferred Stock and Accrued Dividends
Common Stock	10,159,614
Common Stock \| Subsequent to Conversion
Conversion of Preferred Stock and Accrued Dividends
Common Stock		11,368,742
Series A convertible preferred stock \| Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		212,754
Series B convertible preferred stock \| Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		36,019
Series B-1 convertible preferred stock \| Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		727,643
Series C convertible preferred stock \| Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		4,623,523
Paid-in-Kind Dividend Shares		964,667
Series D convertible preferred stock \| Prior to Conversion
Conversion of Preferred Stock and Accrued Dividends
Preferred Shares		4,559,675
Paid-in-Kind Dividend Shares		244,461

Shareholders’ Equity - Common Stock (Details)	12 Months Ended
Shareholders’ Equity - Common Stock (Details)	Dec. 31, 2015 Vote
Shareholder’s Equity
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, 2015 $ / shares	Dec. 31, 2014 $ / shares
Equity transactions
Par value (in dollars per share)	$ 0.001	$ 0.001	$ 0.001
Par value (in dollars per share)		$ 0.001	$ 0.001
Common Stock
Equity transactions
Exchange ratio	0.0667
Series A convertible preferred stock
Equity transactions
Exchange ratio	0.0667
Par value (in dollars per share)	$ 0.001
Series B convertible preferred stock
Equity transactions
Exchange ratio	0.0667
Par value (in dollars per share)	$ 0.001
Series B-1 convertible preferred stock
Equity transactions
Exchange ratio	0.0667
Par value (in dollars per share)	$ 0.001
Series C convertible preferred stock
Equity transactions
Exchange ratio	0.0667
Par value (in dollars per share)	$ 0.001
Series D convertible preferred stock
Equity transactions
Exchange ratio	0.0667
Par value (in dollars per share)	$ 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	Oct. 06, 2015
Common Stock \| Private Placement
Class of Stock [Line Items]
Shares issued (in shares)				2,395,010
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			$ 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	2,395,010
Share price (in dollars per share)	$ 7.00	$ 7.00
Proceeds from issuance of common stock in private placement	$ 16.6

Stock Option Plans - Plan Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 29, 2015	Dec. 31, 2008
Stock Options
Number of Shares
Outstanding at beginning of period (in shares)				500,911	354,833	31,712
Granted (in shares)				1,057,082	234,447	329,323
Exercised (in shares)				(28,516)	(80,816)	(226)
Forfeited/canceled (in shares)				(18)	(7,553)	(5,976)
Outstanding at end of period (in shares)			354,833	1,529,459	500,911	354,833	31,712
Exercisable at end of period (in shares)				356,661
Weighted Average Exercise Price
Outstanding at beginning of period (in dollars per share)				$ 4.95	$ 2.40	$ 7.50
Granted (in dollars per share)				6.82	8.10	1.95
Exercised (in dollars per share)				2.36	2.40	2.40
Forfeited/canceled (in dollars per share)				7.50	4.70	3.50
Outstanding at end of period (in dollars per share)			$ 2.40	6.29	$ 4.95	$ 2.40	$ 7.50
Exercisable at end of period (in dollars per share)				$ 4.56
Additional disclosures
Weighted Average Remaining Contractual Life				9 years	8 years 6 months 7 days	8 years 9 months 18 days	5 years 10 months 2 days
Weighted Average Remaining Contractual Life, Exercisable at end of period				7 years 7 months 10 days
Exercised intrinsic value				$ 160	$ 383	$ 440
Exercisable, Intrinsic Value				820
Outstanding, Intrinsic Value				985
Fair Value of Options Vested				$ 858	$ 198	$ 132
ESPP
Stock Option Plans
Additional stock option and stock purchase rights available for grant				167,180
Percentage of discount for employees under ESPP				15.00%
Purchase price as a percentage over fair value under ESPP				85.00%
Shares issued during the period under ESPP				0
2008 Plan
Stock Option Plans
Number of stock option and stock purchase rights available for grant	1,061,585	669,935	554,782			554,782			330,582
Expiration period				10 years
Additional stock option and stock purchase rights available for grant	391,650	115,153	224,200
Number of Shares
Outstanding at end of period (in shares)				800,478
2015 Plan
Stock Option Plans
Number of stock option and stock purchase rights available for grant				2,472,278				1,671,800

Stock Option Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based compensation expense allocation
Stock-based compensation expense	$ 985	$ 408	$ 163
2015 Plan \| Stock Options
Stock-based compensation expense allocation
Unrecognized compensation cost	$ 5,200
Unrecognized compensation cost, period of recognition	3 years 9 months 18 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	$ 306	110	55
General and administrative expense.
Stock-based compensation expense allocation
Stock-based compensation expense	$ 679	$ 298	$ 108

Stock option Plans - Fair value of stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Fair value assumptions
Stock-based compensation, tax benefit	$ 0	$ 0	$ 0
Stock Options
Fair value assumptions
Risk free interest rate, minimum (as a percent)	1.54%	1.80%	0.90%
Risk free interest rate, maximum (as a percent)	1.98%	2.80%	2.00%
Expected volatility, minimum (as a percent)	77.50%	75.30%	74.70%
Expected volatility, maximum (as a percent)	84.70%	85.40%	76.20%
Weighted-average grant date fair value per share (in dollars per share)	$ 4.73	$ 5.40	$ 1.95
Stock Options \| Minimum
Fair value assumptions
Expected life (in years)	5 years 10 months 24 days	5 years 9 months 18 days	5 years 7 months 6 days
Stock Options \| Maximum
Fair value assumptions
Expected life (in years)	6 years 8 months 12 days	6 years 1 month 6 days	6 years 1 month 6 days

Income Taxes - Effective Income Tax Rate and Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes
Provision for income taxes	$ 0
Increase in Valuation allowance	9,000
Effective Income Tax Rate Reconciliation
Income tax benefit computed at federal statutory tax rate	(8,494)	$ (5,383)	$ (2,188)
Change in valuation allowance	9,002	5,675	2,264
General business credits	(661)	(386)	(32)
Change in fair value of option liability			(115)
Other	153	94	$ 71
Total	0
Interest and penalties related to income taxes	0	0
Components of deferred tax assets and liabilities:
Net operating loss carryforwards	19,562	12,414
Depreciation and amortization	1,207	507
Stock-based compensation	260	71
Credit carryforwards	1,147	444
Prepaid expenses		(49)
Accrued liabilities	22,440	13,417
Total deferred tax assets	264	30
Valuation allowance	$ (22,440)	$ (13,417)

Income Taxes - Net Operating Loss Carryforwards (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Federal
Net Operating Loss Carryforwards
Net operating loss carryforwards	$ 57,500	$ 36,500

Income Taxes - Tax Credits (Details) - Research and Development. - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Tax Credits
Tax credit carryforwards	$ 985	$ 405
State
Tax Credits
Tax credit carryforwards	$ 162

Income Taxes - Other (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Other (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Taxes
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, 2015	Dec. 31, 2014	Dec. 31, 2013
Shared Services
Sublease, option to terminate, period	6 months
Shared Services Agreement with Asuragen
Shared Services
Expenses	$ 490	$ 506	$ 908
Sublease Agreement with Asuragen
Shared Services
Expenses	$ 89	$ 15

Retirement Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Retirement Plan (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Retirement Plan
Employee eligibility, period of service	90 days
Employer contributions	$ 117	$ 91	$ 64

License Agreements (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
License Agreements (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Dec. 31, 2015
Rosetta Genomics
License Agreements
Up-front and milestone payments	$ 1,600
Aggregate payments to be made for each licensed product upon achievement of certain development and regulatory milestones		$ 3,000
Marina Biotech
License Agreements
Up-front and milestone payments		2,100
Aggregate payments to be made for each licensed product upon achievement of certain development and regulatory milestones		6,000
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
Maximum cap on all milestone payments per product		10,000
Aggregate of all remaining development and regulatory milestone payments upon additional indications		4,000
Yale University
License Agreements
Maximum cap on all milestone payments per product		$ 600

Commitments and Contingencies (Detail) $ in Thousands	Dec. 31, 2015 USD ($)
Asuragen Inc
Remaining commitments
Remaining commitments due in 2016	$ 381

Net Loss Per Share Attributable to Common Stockholders - Computation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net Loss Per Share Attributable to Common Stockholders
Net loss	$ (8,789)	$ (6,231)	$ (5,684)	$ (4,279)	$ (4,378)	$ (5,423)	$ (2,997)	$ (3,036)	$ (24,983)	$ (15,834)	$ (6,436)
Accretion of convertible preferred stock to redemption value									(449)		(831)
Accrued dividends on convertible preferred stock									(3,871)	(2,824)	(1,493)
Net loss attributable to common stockholders	$ (8,890)	$ (7,785)	$ (7,229)	$ (5,397)	$ (5,090)	$ (6,135)	$ (3,701)	$ (3,732)	$ (29,303)	$ (18,658)	$ (8,760)
Weighted‑average number of common shares—basic and diluted									5,010,323	64,131	1,987
Net loss per share attributable to common stockholders - basic and diluted									$ (5.85)	$ (291.00)	$ (4,408.65)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net Loss Per Share Attributable to Common Stockholders - Dilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	9,450,949	6,100,850	5,954,773
Convertible Preferred Stock
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	7,921,490	5,599,939	5,599,939
Options to purchase common stock
Potentially dilutive securities
Potentially dilutive securities excluded from the computation of weighted average common shares outstanding	1,529,459	500,911	354,834

Selected Quarterly Data (unaudited) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating expenses:
Research and Development	$ 6,363	$ 4,683	$ 4,499	$ 3,402	$ 3,501	$ 2,788	$ 2,068	$ 2,188	$ 18,947	$ 10,545	$ 4,391
General and Administrative	2,462	1,556	1,185	877	877	715	929	848	6,080	3,369	2,384
Write-off of offering costs						1,920				1,920
Total operating expenses	8,825	6,239	5,684	4,279	4,378	5,423	2,997	3,036	25,027	15,834	6,775
Other (income)	(36)	(8)							(44)		(339)
Net loss	(8,789)	(6,231)	(5,684)	(4,279)	(4,378)	(5,423)	(2,997)	(3,036)	(24,983)	(15,834)	(6,436)
Net loss attributable to common stockholders	$ (8,890)	$ (7,785)	$ (7,229)	$ (5,397)	$ (5,090)	$ (6,135)	$ (3,701)	$ (3,732)	$ (29,303)	$ (18,658)	$ (8,760)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details