Synlogic (SYBX) 10-Q 9 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	May 02, 2017
Document and Entity Information
Entity Registrant Name	Mirna Therapeutics, Inc.
Entity Central Index Key	1,527,599
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		20,856,693
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1

Condensed Balance Sheets

Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 17,121	$ 16,432
Short-term marketable securities	40,408	44,066
Prepaid expenses and other current assets	620	882
Total current assets	58,149	61,380
Property and equipment, net	26	354
Restricted cash	2,433	2,432
Total assets	60,608	64,166
Current Liabilities:
Accounts payable	371	361
Accrued expenses	4,486	2,400
Total current liabilities	4,857	2,761
Lease obligations, long-term	0	1,053
Total liabilities	4,857	3,814
Stockholders’ Equity (Deficit):
Preferred stock, $0.001 par value, 5,000,000 shares authorized at March 31, 2017 and December 31, 2016; 0 shares outstanding at March 31, 2017 and December 31, 2016	0	0
Common stock, $0.001 par value; 250,000,000 shares authorized at March 31, 2017 and December 31, 2016; 20,856,693 and 20,841,393 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	21	21
Additional paid in capital	163,518	163,126
Accumulated deficit	(107,771)	(102,791)
Other comprehensive loss	(17)	(4)
Total stockholders’ equity	55,751	60,352
Total liabilities and stockholders’ equity	$ 60,608	$ 64,166

Condensed Balance Sheets (Paren

Condensed Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	250,000,000	250,000,000
Common stock, shares issued (in shares)	20,856,693	20,841,393
Common stock, shares outstanding (in shares)	20,856,693	20,841,393

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development	$ 242	$ 4,523
General and administrative	2,264	2,130
Restructuring charges	2,557	0
Restructuring charges	5,063	6,653
Other income:
Interest income	86	82
Net loss attributable to common stockholders	(4,977)	(6,571)
Other comprehensive loss:
Unrealized gain/ (loss) on available for sale securities, net of tax	(13)	9
Total other comprehensive loss	$ (4,990)	$ (6,562)
Net loss per share attributable to common stockholders—basic and diluted (in USD per share)	$ (0.24)	$ (0.32)
Common shares used to compute basic and diluted net loss per share attributable to common stockholders (in shares)	20,850,494	20,830,555

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net loss	$ (4,977)	$ (6,571)
Adjustment to reconcile net loss to net cash used in operating activities:
Restructuring charges	2,557	0
Depreciation and amortization	5	19
Stock-based compensation	364	447
Net amortization of premium/ discounts on marketable securities	87	19
Changes in operating assets and liabilities:
Prepaid expenses and other assets	262	(192)
Accounts payable	10	(2,448)
Accrued expenses	(1,524)	(247)
Net cash used in operating activities	(3,216)	(8,973)
Investing activities
Purchases of marketable securities	(12,019)	(27,722)
Maturities of marketable securities	15,577	0
Proceeds from the sale of equipment	325	0
Purchases of property and equipment	(3)	(143)
Net cash provided by/ (used in) investing activities	3,880	(27,865)
Financing activities
Proceeds from the exercise of stock options	25	0
Cash provided by financing activities	25	0
Net increase (decrease) in cash and cash equivalents	689	(36,838)
Cash and cash equivalents at beginning of period	16,432	89,713
Cash and cash equivalents at end of period	$ 17,121	$ 52,875

Nature of Business and Basis of

Nature of Business and Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business and Basis of Presentation	Nature of Business and Basis of Presentation Nature of business Mirna Therapeutics, Inc. (“Mirna” or “the Company”) is a biopharmaceutical company that has historically focused on microRNA-based oncology therapeutics. The Company was incorporated in Delaware in December 2007 as a wholly‑owned subsidiary of Asuragen, Inc. (“Asuragen”) and was spun out to existing Asuragen stockholders in December 2009. Following the close of the Company's Phase 1 clinical trial of MRX34 in September 2016, the Company began to evaluate its strategic alternatives focusing on enhancing stockholder value, including the possibility of a merger or sale of the Company. Mirna has discontinued further research and development activities (see Note 9) to reduce operating expenses while it evaluates these opportunities. The Company is located in Austin, Texas. The Company continues to be subject to a number of risks common to companies in similar stages of development. Principal among these risks are uncertainties of technological innovations, dependence on key individuals, development of the same or similar technological innovations by the Company’s competitors and protection of proprietary technology. The Company believes that its cash, cash equivalents and marketable securities of $57.5 million at March 31, 2017 will enable the Company to maintain its current and planned operations for at least the next twelve months . Basis of presentation The accompanying interim condensed financial statements as of March 31, 2017 and for the three months ended March 31, 2017 and 2016 , and the related interim information contained within the notes to the financial statements, are unaudited. The unaudited interim condensed financial statements have been prepared in accordance with generally accepted accounting principles for interim financial information and on the same basis as the audited financial statements. In the opinion of management, the accompanying unaudited interim condensed financial statements contain all adjustments which include only normal recurring adjustments necessary to state fairly the Company’s financial position as of March 31, 2017 , and the results of its operations and cash flows for the interim periods ended March 31, 2017 and 2016 . Such adjustments are of a normal and recurring nature. The interim financial data as of March 31, 2017 is not necessarily indicative of the results to be expected for the year ending December 31, 2017 , or for any future period. The accompanying condensed financial statements and related financial information should be read in conjunction with the audited financial statements and related notes thereto for the year ended December 31, 2016 included in the Company’s Form 10-K, most recently filed with the Securities and Exchange Commission on March 15, 2017.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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. Amounts included in the financial statements, such those recorded in restructuring charges, can result from a complex series of judgments about future events and uncertainties and can heavily rely on estimates and assumptions. Actual results could differ from those estimates. Research and development costs Research and development costs are expensed as incurred. 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, development of intellectual property, license fees and other external costs. 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. Clinical Trial and Pre-Clinical Study Accruals Prior to the discontinuation of the Company's research and development activities, the Company estimated pre-clinical study and clinical trial expenses pursuant to contracts with research institutions and contract research organizations that conducted and managed pre-clinical studies and clinical trials on the Company’s behalf. These estimates were based on the level of service performed and the underlying agreement. Further, the Company accrued expenses related to clinical trials based on the level of patient enrollment and other activities according to the related agreements. The Company monitored patient enrollment levels and other activities to the extent reasonably possible and adjusted estimates accordingly. If actual costs incurred or the timing of services varied from the Company's estimate, the Company adjusted the accrual accordingly. On September 20, 2016, the Company announced its decision to close the ongoing Phase 1 study of MRX34 and halted enrollment and dosing of patients in the study. 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 equal to the grant date fair value of stock options on a straight‑line basis over the requisite service period less actual forfeitures. Restructuring charges Following the closing of the Phase 1 MRX34 clinical trial, the Company implemented a workforce reduction in the fourth quarter of 2016 to reduce operating expenses while it evaluates strategic alternatives. The majority of severance and benefits payments were settled during the first quarter of 2017. The Company entered into retention agreements with key employees necessary to close the Phase 1 clinical trial of MRX34 and maintain the continued operations of the Company. Under the retention agreements, employees must remain with the Company until June 30, 2017 or until terminated by the Company without cause prior to such date. The Company has recognized the restructuring liability for such retention agreements over the employees' service period. In accordance with ASC 420, Exit and Disposal Cost Obligations, the Company has also recognized contract termination costs in connection with a leased property it intended to occupy as its corporate headquarters and research facility, as well as a temporary lab in use prior to the discontinuation of the Company's research and development activities. In addition, the Company has recognized asset impairments related to its lab equipment used in the Phase 1 clinical trial, construction in process, and other property and equipment for which the Company does not expect to receive a future benefit. 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 prices in active markets for identical assets or liabilities. • Level 2 – Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. The carrying amounts reflected in the balance sheets for cash, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their fair values at March 31, 2017 and December 31, 2016 , due to their short‑term nature. 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 three months ended March 31, 2017 or 2016 . Restricted Cash Restricted cash consists of cash amounts held for specific or limited purposes and, therefore, not available for general operating activities. In June 2016, the Company secured a standby letter of credit of $2.4 million for the benefit of the landlord for the Company's lease of approximately 23,578 square feet of office and laboratory space in the event of default. The restricted cash consists of cash providing security under the terms of the lease described in Note 10. As a result of the Lease Termination Agreement and Release described in Note 12, the landlord will release the letter of credit described above to the Company and the balance of restricted cash will be reclassified to cash and cash equivalents. Marketable Securities Marketable securities with maturities at purchase beyond one year, but less than twenty-four months, may be classified as short-term marketable securities based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Marketable securities with maturities at purchase beyond twenty-four months are classified as non-current. Available-for-sale securities are maintained by an investment manager and may consist of U.S. Treasury securities and government agency securities and corporate debt securities. Available-for-sale securities are carried at fair value with the unrealized gains and losses included in other comprehensive loss as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in other income. If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other-than-temporary.” If the decline is other-than-temporary, the investment is marked to market through a charge to the Company’s statement of operations and comprehensive loss. Recently Issued and Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share Based Payment Accounting ("ASU 2016-09") as part of the FASB simplification initiative. The new standard provides for changes to accounting for stock compensation including 1) excess tax benefits and tax deficiencies related to share-based payment awards will be recognized as income tax expense in the reporting period in which they occur; 2) excess tax benefits will be classified as an operating activity in the statement of cash flow; 3) the option to elect to estimate forfeitures or account for them when they occur; and 4) increase tax withholding requirements threshold to qualify for equity classification. We adopted ASU 2016-09 in the quarter ended March 31, 2017 with an effective date of January 1, 2017 and made a policy election to account for forfeitures as they occur. In addition, the Company increased both its net operating loss deferred tax asset and its valuation allowance upon adoption of ASU 2016-09. This did not have an impact on net stockholders' equity as the incremental deferred tax assets were fully offset by a corresponding increase in the deferred tax asset valuation allowance as of March 31, 2017. The cumulative effect of adoption was recorded in the quarter ended March 31, 2017 and did not have a material impact on our condensed financial statements.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities The following table summarizes the available-for-sale securities held at March 31, 2017 and December 31, 2016 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2017 U.S. government agency securities and treasuries $ 39,599 $ — $ (17 ) $ 39,582 Corporate debt securities 826 — — 826 Total available-for-sale securities $ 40,425 $ — $ (17 ) $ 40,408 Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2016 U.S. government agency securities and treasuries $ 42,516 $ 4 $ (8 ) $ 42,512 Corporate debt securities 1,554 — — 1,554 Total available-for-sale securities $ 44,070 $ 4 $ (8 ) $ 44,066 There were no available-for-sale securities held as of March 31, 2017 that had remaining maturities greater than one year.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following table sets forth the Company’s assets that are measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 (in thousands): Total Quoted Significant Significant March 31, 2017 Assets: Cash and cash equivalents Cash $ 2,399 $ 2,399 $ — $ — Money market funds 14,722 14,722 $ — $ — Total cash and cash equivalents 17,121 17,121 — — Marketable securities U.S. government agency securities and treasuries 39,582 — 39,582 — Corporate debt securities 826 — 826 — Total marketable securities 40,408 — 40,408 — Restricted cash 2,433 2,433 — — Total assets $ 59,962 $ 19,554 $ 40,408 $ — Total Quoted Significant Significant December 31, 2016 Assets: Cash and cash equivalents Cash $ 2,785 $ 2,785 $ — $ — Money market funds $ 9,647 $ 9,647 $ — $ — US government agency securities and treasuries $ 4,000 — 4,000 Total cash and cash equivalents 16,432 12,432 4,000 — Marketable securities U.S. government agency securities and treasuries 42,512 — 42,512 — Corporate debt securities 1,554 — 1,554 — Total marketable securities 44,066 — 44,066 — Restricted cash 2,432 2,432 — — Total assets $ 62,930 $ 14,864 $ 48,066 $ — Cash and cash equivalents The Company considers all highly liquid securities with original final maturities of three months or less from the date of purchase to be cash equivalents. As of March 31, 2017 and December 31, 2016 , cash and cash equivalents are comprised of cash, money market accounts, and U.S. government agency securities and treasuries. Marketable securities The cost of available-for-sale securities is adjusted for amortization of premiums and accretion of discounts to maturity. At March 31, 2017 and December 31, 2016 , the balance in the Company’s accumulated other comprehensive loss was composed solely of activity related to the Company’s available-for-sale marketable securities. The Company has not realized material gains or losses on sales of available-for-sale investment securities during any of the periods presented. As of March 31, 2017 , available for sale securities of approximately $40.0 million were in an unrealized loss position of $17,000 . The Company has the intent and ability to hold such securities until recovery. The Company determined that there were no material changes in the credit risk of the above investments. The Company did not hold any investments with an other-than-temporary impairment as of March 31, 2017 and December 31, 2016 .

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consisted of the following (in thousands): March 31, December 31, Furniture, computers and equipment $ 62 $ 385 Accumulated depreciation (36 ) (31 ) $ 26 354 Depreciation expense was approximately $5,000 and $19,000 for the three months ended March 31, 2017 and 2016 , respectively. In February 2017, the Company entered into an Asset Purchase Agreement for the sale of certain of the Company's lab equipment ("Lab Equipment") with a third party for cash consideration of $325,000 . The selling price of the Lab Equipment approximated its book value at December 31, 2016.

Common Stock

Common Stock	3 Months Ended
	Mar. 31, 2017
Stockholders' Equity Note [Abstract]
Common Stock	Common 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. • The holders of shares of common stock are entitled to receive dividends, if and when declared by the Company’s board of directors. Since inception, no cash dividends have been declared. Offerings In September 2015, the Company entered into a new grant contract with Cancer Prevention and Research Institute of Texas (“CPRIT”), in connection with an award of approximately $16.8 million . The award was in the form of an agreement by CPRIT to purchase $16.8 million of shares of common stock of the Company in a private placement concurrent with the initial public offering of the Company’s common stock. On October 5, 2015, CPRIT purchased 2,395,010 shares of the Company’s common stock at $7.00 per share. Net proceeds from the private placement, after related transaction offering costs, were approximately $16.6 million . In October 2015, the Company issued 6.25 million shares of common stock in an underwritten public offering, with a price of $7.00 per share. The underwriters purchased an additional 704,962 shares of common stock pursuant to their 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.

Stock Option Plans

Stock Option Plans	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plans	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 from the date of grant. 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, 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 462,934 options outstanding in the 2008 Plan at March 31, 2017 may be transferred to the 2015 Plan if awards thereunder terminate, expire or lapse for any reason without the delivery of shares to the holder thereof. As of March 31, 2017, 316,932 shares have been transferred from the 2008 Long Term Incentive Plan to the 2015 Equity Incentive Plan for awards that have terminated, expired, or lapsed. Under the 2015 Plan, 1,671,800 shares of the Company’s common stock were initially authorized and reserved for issuance. In addition, 1,041,526 shares of the Company's common stock were authorized and reserved for issuance in the first quarter of 2017, for a total of 3,030,258 authorized for grant under the 2015 Plan at March 31, 2017. 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. Shares available for future purchase under the ESPP were 369,960 at March 31, 2017 ; however, as of December 2016, the Company has suspended future issuances of the Company's common stock under the ESPP plan. Stock Option Activity The Company’s stock option activity for the three months ended March 31, 2017 was as follows: Weighted‑ Average Weighted‑Average Number Exercise Contractual of Shares Price Life (years) Outstanding at December 31, 2016 1,905,214 $ 5.39 7.49 Granted — — Exercised (15,300 ) 1.65 Forfeited/canceled (278,593 ) 5.52 Outstanding at March 31, 2017 1,611,321 $ 5.40 8.12 Options exercisable at March 31, 2017 692,798 $ 5.45 7.30 Stock Compensation Expense Total stock-based compensation expense for the three and three months ended March 31, 2017 was recognized as follows in the statements of comprehensive loss (in thousands): Three Months Ended 2017 2016 Research and development expense $ 41 $ 171 General and administrative expense 323 276 Total stock based compensation $ 364 $ 447 As of March 31, 2017 , there was approximately $2.9 million of unrecognized compensation cost related to the stock options granted under the 2015 Plan, which is expected to be amortized over a weighted-average period of 2.4 years . There were no restricted stock units or stock appreciation rights granted under the 2015 Plan as of March 31, 2017 .

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company has not recorded a provision for income taxes as of March 31, 2017 due to reported net losses since inception. During the three months ended March 31, 2017 and 2016 , the Company had no interest and penalties related to income taxes. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. 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. The Company files income tax returns in the U.S. federal and Texas jurisdictions. The statute of limitations for assessment by the Internal Revenue Service (“IRS”) is open for tax years ending December 31, 2015, 2014, and 2013, although carryforward attributes that were generated for tax years prior to 2013 may still be adjusted upon examination by the IRS if they either have been, or will be, used in a future period. The 2010 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.

Restructuring Charges

Restructuring Charges	3 Months Ended
	Mar. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges On September 20, 2016, Mirna announced its decision to close the ongoing Phase 1 study of MRX34 and voluntarily halted the enrollment and dosing of patients in the study. Following the announcement, the Company received verbal notice from the U.S. Food and Drug Administration ("FDA") on September 28, 2016 that its Investigational New Drug MRX34 had been placed on full clinical hold. Following the Company's announcement and notification from the FDA, the Company's board of directors approved a reduction of the total number of full-time employees from 36 to 12 . As of March 31, 2017, the total number of full-time employees was 7 . The Company also committed to retention payments to certain key employees if such employees remained with the Company until June 30, 2017 or were terminated by Mirna without cause prior to such date. Total estimated restructuring charges are approximately $7.1 million and are expected to be incurred through June 30, 2017. Cumulative restructuring charges of $7.0 million have been recognized as of March 31, 2017, of which $4.4 million was recognized during the year ended December 31, 2016 and include a non-cash impairment charge of $1.4 million . Restructuring charges were as follows (in thousands): Three months ended March 31, 2017 2016 Employee severance and related costs $ 204 — Contract termination costs 2,353 — Total restructuring charges $ 2,557 — The accrued restructuring activity for the three months ended March 31, 2017 was as follows (in thousands): Employee severance and related costs Contract Termination Costs Total Balance at December 31, 2016 $ 1,097 $ 1,565 $ 2,662 Restructuring charges and adjustments 204 2,353 2,557 Cash payments (1,219 ) (100 ) (1,319 ) Balance at March 31, 2017 $ 82 $ 3,818 $ 3,900 The total accrued restructuring balance of $3.9 million has been presented as a current liability within accrued expenses. Employee severance and related costs Employee severance and benefits costs recorded in restructuring charges for the three months ended March 31, 2017 included $0.2 million in accrued retention costs, which are being ratably recognized over the respective employee's service period. Contract termination costs Contract termination costs recorded in restructuring charges for the year ended December 31, 2016 of $1.5 million related to the Company's determination to cease use and not occupy the Company's headquarters and research facility in connection with the lease the Company entered into in June 2016 (see Note 10). In connection with this determination, the Company recorded a liability of $1.6 million , which was equal to the fair value of the lease obligation at the cease-use date of November 20, 2016. The Company estimated the liability for the contract termination costs associated with the lease as of the cease-use date based on the discounted present value of the remaining lease payments, considering future estimated sublease income, estimated broker fees and contractual executory costs. In May 2017, the Company and its landlord entered into the Lease Settlement (defined in Note 12) to terminate the lease described in Note 10 for consideration of approximately $3.8 million ("the Settlement Amount"). The Lease Settlement is contingent upon the landlord's execution of a new lease with a third party prior to May 30, 2017, which date the landlord may extend, at its sole option, by 60 days. The Company adjusted its liability for contract termination costs to the Settlement Amount, resulting in an adjustment of $2.4 million recorded in restructuring charges for the three months ended March 31, 2017. See Note 12 for additional discussion surrounding the termination of the lease. Asset impairment costs Following the discontinuation of research and development activities and corresponding workforce reduction, the Company determined that certain property and equipment was impaired and recognized an impairment charge of $1.4 million in restructuring expense in the statement of operations for the year ended December 31, 2016. Of the total impairment charge, approximately $555,000 relates to the impairment of the Lab Equipment which was sold for $325,000 in February 2017 (see Note 5). In addition, the Company recognized an impairment of $591,000 during the year ended December 31, 2016 in construction in progress for the Company's planned headquarters and research facility associated with the termination of the lease contract discussed above. Further, following the workforce reduction, the Company sold or donated its remaining office equipment with the exception of nominal office equipment necessary to continue administrative functions and the closure of its Phase 1 clinical trial, resulting in an impairment of furniture, computers and equipment and leasehold improvements of $256,000 recognized during the year ended December 31, 2016.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Lease In June 2016, the Company entered into a lease for its corporate headquarters and research facility in Austin, Texas (the “Headquarters”) under an operating lease agreement (the “Lease”). The initial term of the Lease is for a 123 -month period, with the option to extend the lease for up to two consecutive 60 -month terms. In November 2016, following the workforce reduction described in Note 9, the Company determined not to occupy and ceased use of the headquarters and research facility under the Lease. See Note 9 to the financial statements for further information on accounting for the Lease. The lease provides annual base rent of approximately $600,000 in the first year after a three -month rent free period following the Commencement Date, with subsequent annual increases of approximately 3% in the annual base rent. In connection with the lease, the landlord has provided a tenant improvement allowance of approximately $1.9 million to be used by the Company to build-out certain improvements to the Headquarters. There have been no draws on the improvement allowance as of March 31, 2017 . Mirna has obtained a standby letter of credit for the initial amount of approximately $2.4 million , which may be drawn down by the landlord in the event of default. If Mirna meets certain requirements, the amount due under the Letter of Credit may be reduced to approximately $800,000 . Under the Lease agreement, future minimum payments payable are approximately as follows: Operating Period ending December 31, Lease 2017 (nine months) $ 450,929 2018 614,855 2019 633,364 2020 652,340 2021 and thereafter 4,565,888 Total $ 6,917,376 In May 2017, the Company and its landlord entered into the Lease Settlement (defined in Note 12) to terminate the Lease for consideration of approximately $3.8 million . See Note 12 for additional discussion surrounding the termination of the Lease. CPRIT In August 2010, the Company entered into a grant contract ("2010 Grant Contract") with the Cancer Prevention and Research Institute of Texas (CPRIT), under which it received a $ 10.3 million commercialization award from the State of Texas through CPRIT. CPRIT was established to expedite innovation and commercialization in the area of cancer research and to enhance access to evidence-based prevention programs and services throughout the State of Texas. The award was a three -year award that was funded annually, and the contract terminated on January 31, 2014, subject to the Company's obligations to make certain payments that survive termination. Under the terms of the award, the Company will be required to pay to CPRIT a portion of the Company's revenues from sales of certain products by the Company, or received from our licensees or sublicensees, at a percentage in the low single digits until the aggregate amount of such payments equals a specified multiple of the grant amount, and thereafter at a rate of less than one percent, subject to the Company's right, under certain circumstances, to make a one-time payment in a specified amount to CPRIT to buy out such payment obligations. The 2010 grant contract also contains a provision that provides for repayment to CPRIT some amount not to exceed the full amount of the grant proceeds under certain specified circumstances involving relocation of our principal place of business outside Texas.

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	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): Three Months Ended 2017 2016 Net loss attributable to common stockholders—basic and diluted 4,977 6,571 Weighted-average number of common shares—basic and diluted 20,850,494 20,830,555 Net loss per share attributable to common stockholders—basic and diluted $ (0.24 ) $ (0.32 ) As of March 31, 2017 and 2016 the Company has excluded 1,611,321 and 1,915,709 potentially dilutive stock options outstanding, respectively, from the computation of diluted weighted average common shares outstanding, prior to the use of the treasury stock method or if-converted method, because including them would have had an anti- dilutive effect due to the losses reported. As the Company incurred a net loss for the three months ended March 31, 2017 and March 31, 2016 there is no income allocation required under the two‑class method or dilution attributed to weighted‑average shares outstanding in the computation of diluted loss per share attributable to common stockholders.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Lease Termination In May 2017, the Company and G&I VII Encino Trace II LP (the "Landlord") entered into a Lease Termination Agreement and Release (the "Lease Settlement") to terminate the lease described in Note 10 for consideration of approximately $3.8 million (the "Settlement Amount"). This agreement is contingent upon the Landlord's execution of a new lease with a third party prior to May 30, 2017 (the "Contingency Date"). The Landlord may extend the Contingency Date, at its sole option, for a period of up to 60 days. The Lease Settlement includes standard representations and warranties and releases both the Company and the Landlord from their mutual obligations under the Lease, provided, for purposes of the Landlord's release, the Company does not file for bankruptcy or otherwise make an assignment for the benefit of creditors within 90 days of the Landlord's receipt of the Settlement Amount.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Use of estimates	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. Amounts included in the financial statements, such those recorded in restructuring charges, can result from a complex series of judgments about future events and uncertainties and can heavily rely on estimates and assumptions. Actual results could differ from those estimates.
Research and development costs	Research and development costs Research and development costs are expensed as incurred. 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, development of intellectual property, license fees and other external costs. 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.
Clinical Trial and Pre-Clinical Study Accruals	Clinical Trial and Pre-Clinical Study Accruals Prior to the discontinuation of the Company's research and development activities, the Company estimated pre-clinical study and clinical trial expenses pursuant to contracts with research institutions and contract research organizations that conducted and managed pre-clinical studies and clinical trials on the Company’s behalf. These estimates were based on the level of service performed and the underlying agreement. Further, the Company accrued expenses related to clinical trials based on the level of patient enrollment and other activities according to the related agreements. The Company monitored patient enrollment levels and other activities to the extent reasonably possible and adjusted estimates accordingly. If actual costs incurred or the timing of services varied from the Company's estimate, the Company adjusted the accrual accordingly. On September 20, 2016, the Company announced its decision to close the ongoing Phase 1 study of MRX34 and halted enrollment and dosing of patients in the study.
Stock-based compensation	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 equal to the grant date fair value of stock options on a straight‑line basis over the requisite service period less actual forfeitures.
Restructuring charges	Restructuring charges Following the closing of the Phase 1 MRX34 clinical trial, the Company implemented a workforce reduction in the fourth quarter of 2016 to reduce operating expenses while it evaluates strategic alternatives. The majority of severance and benefits payments were settled during the first quarter of 2017. The Company entered into retention agreements with key employees necessary to close the Phase 1 clinical trial of MRX34 and maintain the continued operations of the Company. Under the retention agreements, employees must remain with the Company until June 30, 2017 or until terminated by the Company without cause prior to such date. The Company has recognized the restructuring liability for such retention agreements over the employees' service period. In accordance with ASC 420, Exit and Disposal Cost Obligations, the Company has also recognized contract termination costs in connection with a leased property it intended to occupy as its corporate headquarters and research facility, as well as a temporary lab in use prior to the discontinuation of the Company's research and development activities. In addition, the Company has recognized asset impairments related to its lab equipment used in the Phase 1 clinical trial, construction in process, and other property and equipment for which the Company does not expect to receive a future benefit.
Fair value measurements	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 prices in active markets for identical assets or liabilities. • Level 2 – Quoted prices for similar assets and liabilities in active markets, quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability. • Level 3 – Unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date. The carrying amounts reflected in the balance sheets for cash, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their fair values at March 31, 2017 and December 31, 2016 , due to their short‑term nature. 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 three months ended March 31, 2017 or 2016 .
Restricted Cash	Restricted Cash Restricted cash consists of cash amounts held for specific or limited purposes and, therefore, not available for general operating activities.
Marketable Securities	Marketable Securities Marketable securities with maturities at purchase beyond one year, but less than twenty-four months, may be classified as short-term marketable securities based on their highly liquid nature and because such marketable securities represent the investment of cash that is available for current operations. Marketable securities with maturities at purchase beyond twenty-four months are classified as non-current. Available-for-sale securities are maintained by an investment manager and may consist of U.S. Treasury securities and government agency securities and corporate debt securities. Available-for-sale securities are carried at fair value with the unrealized gains and losses included in other comprehensive loss as a component of stockholders’ equity until realized. Any premium or discount arising at purchase is amortized and/or accreted to interest income and/or expense over the life of the instrument. Realized gains and losses are determined using the specific identification method and are included in other income. If any adjustment to fair value reflects a decline in value of the investment, the Company considers all available evidence to evaluate the extent to which the decline is “other-than-temporary.” If the decline is other-than-temporary, the investment is marked to market through a charge to the Company’s statement of operations and comprehensive loss.
Recently Issued Accounting Pronouncements	Recently Issued and Adopted Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share Based Payment Accounting ("ASU 2016-09") as part of the FASB simplification initiative. The new standard provides for changes to accounting for stock compensation including 1) excess tax benefits and tax deficiencies related to share-based payment awards will be recognized as income tax expense in the reporting period in which they occur; 2) excess tax benefits will be classified as an operating activity in the statement of cash flow; 3) the option to elect to estimate forfeitures or account for them when they occur; and 4) increase tax withholding requirements threshold to qualify for equity classification. We adopted ASU 2016-09 in the quarter ended March 31, 2017 with an effective date of January 1, 2017 and made a policy election to account for forfeitures as they occur. In addition, the Company increased both its net operating loss deferred tax asset and its valuation allowance upon adoption of ASU 2016-09. This did not have an impact on net stockholders' equity as the incremental deferred tax assets were fully offset by a corresponding increase in the deferred tax asset valuation allowance as of March 31, 2017. The cumulative effect of adoption was recorded in the quarter ended March 31, 2017 and did not have a material impact on our condensed financial statements.

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Summary of Available-for-sale Securities Held	The following table summarizes the available-for-sale securities held at March 31, 2017 and December 31, 2016 (in thousands): Amortized Cost Unrealized Gains Unrealized Losses Fair Value March 31, 2017 U.S. government agency securities and treasuries $ 39,599 $ — $ (17 ) $ 39,582 Corporate debt securities 826 — — 826 Total available-for-sale securities $ 40,425 $ — $ (17 ) $ 40,408 Amortized Cost Unrealized Gains Unrealized Losses Fair Value December 31, 2016 U.S. government agency securities and treasuries $ 42,516 $ 4 $ (8 ) $ 42,512 Corporate debt securities 1,554 — — 1,554 Total available-for-sale securities $ 44,070 $ 4 $ (8 ) $ 44,066

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Company's Assets that are Measured at Fair Value on a Recurring Basis	The following table sets forth the Company’s assets that are measured at fair value on a recurring basis as of March 31, 2017 and December 31, 2016 (in thousands): Total Quoted Significant Significant March 31, 2017 Assets: Cash and cash equivalents Cash $ 2,399 $ 2,399 $ — $ — Money market funds 14,722 14,722 $ — $ — Total cash and cash equivalents 17,121 17,121 — — Marketable securities U.S. government agency securities and treasuries 39,582 — 39,582 — Corporate debt securities 826 — 826 — Total marketable securities 40,408 — 40,408 — Restricted cash 2,433 2,433 — — Total assets $ 59,962 $ 19,554 $ 40,408 $ — Total Quoted Significant Significant December 31, 2016 Assets: Cash and cash equivalents Cash $ 2,785 $ 2,785 $ — $ — Money market funds $ 9,647 $ 9,647 $ — $ — US government agency securities and treasuries $ 4,000 — 4,000 Total cash and cash equivalents 16,432 12,432 4,000 — Marketable securities U.S. government agency securities and treasuries 42,512 — 42,512 — Corporate debt securities 1,554 — 1,554 — Total marketable securities 44,066 — 44,066 — Restricted cash 2,432 2,432 — — Total assets $ 62,930 $ 14,864 $ 48,066 $ —

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment	Property and equipment consisted of the following (in thousands): March 31, December 31, Furniture, computers and equipment $ 62 $ 385 Accumulated depreciation (36 ) (31 ) $ 26 354

Stock Option Plans (Tables)

Stock Option Plans (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Stock Option Activity	The Company’s stock option activity for the three months ended March 31, 2017 was as follows: Weighted‑ Average Weighted‑Average Number Exercise Contractual of Shares Price Life (years) Outstanding at December 31, 2016 1,905,214 $ 5.39 7.49 Granted — — Exercised (15,300 ) 1.65 Forfeited/canceled (278,593 ) 5.52 Outstanding at March 31, 2017 1,611,321 $ 5.40 8.12 Options exercisable at March 31, 2017 692,798 $ 5.45 7.30
Schedule of Stock Compensation Expense	Total stock-based compensation expense for the three and three months ended March 31, 2017 was recognized as follows in the statements of comprehensive loss (in thousands): Three Months Ended 2017 2016 Research and development expense $ 41 $ 171 General and administrative expense 323 276 Total stock based compensation $ 364 $ 447

Restructuring Charges (Tables)

Restructuring Charges (Tables)	3 Months Ended
	Mar. 31, 2017
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring charges were as follows (in thousands): Three months ended March 31, 2017 2016 Employee severance and related costs $ 204 — Contract termination costs 2,353 — Total restructuring charges $ 2,557 — The accrued restructuring activity for the three months ended March 31, 2017 was as follows (in thousands): Employee severance and related costs Contract Termination Costs Total Balance at December 31, 2016 $ 1,097 $ 1,565 $ 2,662 Restructuring charges and adjustments 204 2,353 2,557 Cash payments (1,219 ) (100 ) (1,319 ) Balance at March 31, 2017 $ 82 $ 3,818 $ 3,900

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments Payable	Under the Lease agreement, future minimum payments payable are approximately as follows: Operating Period ending December 31, Lease 2017 (nine months) $ 450,929 2018 614,855 2019 633,364 2020 652,340 2021 and thereafter 4,565,888 Total $ 6,917,376

Net Loss Per Share Attributab25

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss per Share	The following table summarizes the computation of basic and diluted net loss per share attributable to common stockholders of the Company (in thousands, except share and per share data): Three Months Ended 2017 2016 Net loss attributable to common stockholders—basic and diluted 4,977 6,571 Weighted-average number of common shares—basic and diluted 20,850,494 20,830,555 Net loss per share attributable to common stockholders—basic and diluted $ (0.24 ) $ (0.32 )

Nature of Business and Basis 26

Nature of Business and Basis of Presentation (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017USD ($)
Cash and Cash Equivalents [Line Items]
Cash , cash equivalents and marketable securities	$ 57.5
Minimum
Cash and Cash Equivalents [Line Items]
Period over which cash resources will be sufficient to maintain the company's current and planned operations	12 months

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Details)	3 Months Ended
	Mar. 31, 2017USD ($)	Mar. 31, 2016USD ($)	Jun. 30, 2016USD ($)ft²
Fair value of assets measured at fair value on a recurring basis
Transfers of assets and liabilities between Level 1, Level 2, or Level 3	$ 0	$ 0
Area of lease of office and laboratory space (in sq ft) | ft²			23,578
Standby Letters of Credit
Fair value of assets measured at fair value on a recurring basis
Standby letter of credit	$ 2,400,000		$ 2,400,000

Marketable Securities (Details)

Marketable Securities (Details) - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale securities held
Amortized Cost	$ 40,425,000	$ 44,070,000
Unrealized Gains	0	4,000
Unrealized Losses	(17,000)	(8,000)
Fair Value	40,408,000	44,066,000
Maturities
Available-for-sale securities with remaining maturities greater than one year	0
U.S. government agency securities and treasuries
Available-for-sale securities held
Amortized Cost	39,599,000	42,516,000
Unrealized Gains	0	4,000
Unrealized Losses	(17,000)	(8,000)
Fair Value	39,582,000	42,512,000
Corporate debt securities
Available-for-sale securities held
Amortized Cost	826,000	1,554,000
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	$ 826,000	$ 1,554,000

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	$ 40,408	$ 44,066
Marketable securities
Available for sale securities in an unrealized loss position	40,000
Available for sale securities, unrealized loss	17
Recurring
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	40,408	44,066
Total assets	59,962	62,930
Recurring | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	39,582	42,512
Recurring | Corporate debt securities
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	826	1,554
Recurring | Cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,399	2,785
Recurring | Money market funds
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	14,722	9,647
Recurring | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents		4,000
Recurring | Total cash and cash equivalents
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	17,121	16,432
Recurring | Restricted cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,433	2,432
Recurring | Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Total assets	19,554	14,864
Recurring | Quoted prices in active markets (Level 1) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Recurring | Quoted prices in active markets (Level 1) | Corporate debt securities
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Recurring | Quoted prices in active markets (Level 1) | Cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,399	2,785
Recurring | Quoted prices in active markets (Level 1) | Money market funds
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	14,722	9,647
Recurring | Quoted prices in active markets (Level 1) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents		0
Recurring | Quoted prices in active markets (Level 1) | Total cash and cash equivalents
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	17,121	12,432
Recurring | Quoted prices in active markets (Level 1) | Restricted cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,433	2,432
Recurring | Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	40,408	44,066
Total assets	40,408	48,066
Recurring | Significant other observable inputs (Level 2) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	39,582	42,512
Recurring | Significant other observable inputs (Level 2) | Corporate debt securities
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	826	1,554
Recurring | Significant other observable inputs (Level 2) | Cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant other observable inputs (Level 2) | Money market funds
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant other observable inputs (Level 2) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents		4,000
Recurring | Significant other observable inputs (Level 2) | Total cash and cash equivalents
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	4,000
Recurring | Significant other observable inputs (Level 2) | Restricted cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Total assets	0	0
Recurring | Significant unobservable inputs (Level 3) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Recurring | Significant unobservable inputs (Level 3) | Corporate debt securities
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0	0
Recurring | Significant unobservable inputs (Level 3) | Cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant unobservable inputs (Level 3) | Money market funds
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant unobservable inputs (Level 3) | U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents
Recurring | Significant unobservable inputs (Level 3) | Total cash and cash equivalents
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Recurring | Significant unobservable inputs (Level 3) | Restricted cash
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	$ 0	$ 0

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property and equipment, gross	$ 62		$ 385
Accumulated depreciation	(36)		(31)
Property and equipment, net	26		$ 354
Depreciation expense	5	$ 19
Cash consideration for sale of lab equipment	$ 325	$ 0

Common Stock - Voting and Divid

Common Stock - Voting and Dividends (Details)	3 Months Ended	112 Months Ended
	Mar. 31, 2017vote	Mar. 31, 2017USD ($)
Stockholders' Equity Note [Abstract]
Number of votes per common stock | vote	1
Cash dividends | $		$ 0

Common Stock - Offerings (Detai

Common Stock - Offerings (Details) - USD ($) $ / shares in Units, $ in Millions	Oct. 05, 2015	Oct. 31, 2015	Sep. 30, 2015
Common Stock | Initial Public Offering
Class of Stock [Line Items]
Shares issued (in shares)		6,250,000
Share price (in USD per share)		$ 7
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 contract			$ 16.8
Purchase agreement			$ 16.8
CPRIT | Common Stock | Private Placement
Class of Stock [Line Items]
Shares issued (in shares)	2,395,010
Share price (in USD per share)	$ 7
Proceeds from issuance of common stock in private placement	$ 16.6

Stock Option Plans - Plan Infor

Stock Option Plans - Plan Information (Details) - $ / shares	1 Months Ended			3 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2017	Dec. 31, 2016	Aug. 31, 2015	Dec. 31, 2008
Number of Shares
Outstanding at beginning of period (in shares)				1,905,214
Granted (in shares)				0
Exercised (in shares)				(15,300)
Forfeited/canceled (in shares)				(278,593)
Outstanding at end of period (in shares)				1,611,321	1,905,214
Exercisable at end of period (in shares)				692,798
Weighted Average Exercise Price
Outstanding at beginning of period (in USD per share)				$ 5.39
Granted (in USD per share)				0
Exercised (in USD per share)				1.65
Forfeited/canceled (in USD per share)				5.52
Outstanding at end of period (in USD per share)				5.40	$ 5.39
Exercisable at end of period (in USD per share)				$ 5.45
Additional disclosures
Weighted Average Remaining Contractual Life (years)				8 years 1 month 13 days	7 years 5 months 27 days
Weighted Average Remaining Contractual Life (years), Options exercisable				7 years 3 months 18 days
ESPP
Stock Option Plans
Number of stock options and stock purchase rights available for grant (in shares)				369,960
Percentage of discount for employees under ESPP				15.00%
Purchase price as a percentage of fair value under ESPP				85.00%
2008 Plan
Stock Option Plans
Number of stock options and stock purchase rights available for grant (in shares)	1,061,585	669,935	554,782				330,582
Increase in number of stock options and stock purchase rights available for grant (in shares)	391,650	115,153	224,200
Expiration period				10 years
Shares transferred from the 2008 long term incentive plan to the 2015 equity incentive plan (in shares)				316,932
Number of Shares
Outstanding at end of period (in shares)				462,934
2015 Plan
Stock Option Plans
Number of stock options and stock purchase rights available for grant (in shares)						1,671,800
Increase in number of stock options and stock purchase rights available for grant (in shares)				1,041,526
2008 Plan and 2015 Plan
Stock Option Plans
Number of stock options and stock purchase rights available for grant (in shares)				3,030,258

Stock Option Plans - Stock-Base

Stock Option Plans - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Stock-based compensation expense allocation
Stock based compensation	$ 364	$ 447
Stock Appreciation Rights
Stock-based compensation expense allocation
Awards granted (in shares)	0
2015 Plan | Stock Options
Stock-based compensation expense allocation
Unrecognized compensation cost	$ 2,900
Unrecognized compensation cost, period of recognition	2 years 4 months 24 days
2015 Plan | Restricted Stock Units
Stock-based compensation expense allocation
Awards granted (in shares)	0
Research and development expense
Stock-based compensation expense allocation
Stock based compensation	$ 41	171
General and administrative expense
Stock-based compensation expense allocation
Stock based compensation	$ 323	$ 276

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Interest and penalties related to income taxes	$ 0	$ 0

Restructuring Charges - Narrat

Restructuring Charges - Narrative (Details) $ in Thousands	1 Months Ended		3 Months Ended			6 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2017USD ($)	Feb. 28, 2017USD ($)	Mar. 31, 2017USD ($)employee	Dec. 31, 2016USD ($)	Mar. 31, 2016USD ($)	Mar. 31, 2017USD ($)employee	Jun. 30, 2017USD ($)employee	Dec. 31, 2016USD ($)	Sep. 28, 2016employee
Restructuring Cost and Reserve [Line Items]
Number of employees | employee			7			7			36
Restructuring expense			$ 2,557	$ 4,400		$ 7,000
Non-cash impairment charges				1,400				$ 1,400
Employee severance and related costs			204		$ 0
Contract termination costs			2,353		0			1,500
Accrued restructuring			3,900	2,662		3,900		2,662
Cash consideration for sale of lab equipment			325		$ 0
Lab Equipment
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges								555
Cash consideration for sale of lab equipment		$ 325
Construction in Progress
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges								591
Furniture, Computers, Equipment, and Leasehold Improvements
Restructuring Cost and Reserve [Line Items]
Non-cash impairment charges								256
Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Restructuring expense			2,353
Accrued restructuring			$ 3,818	$ 1,565		$ 3,818		$ 1,565
Scenario, Forecast
Restructuring Cost and Reserve [Line Items]
Number of employees | employee							12
Restructuring expense							$ 7,100
Consideration paid for settlement of lease	$ 3,800
Contingency term for lease termination	60 days

Restructuring Charges - Schedu

Restructuring Charges - Schedule of Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Employee severance and related costs	$ 204	$ 0
Contract termination costs	2,353	0	$ 1,500
Total restructuring charges	$ 2,557	$ 0

Restructuring Charges - Accumu

Restructuring Charges - Accumulated Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Balance at December 31, 2016	$ 2,662
Restructuring charges and adjustments	2,557	$ 4,400	$ 7,000
Cash payments	(1,319)
Balance at March 31, 2017	3,900	2,662	3,900
Employee severance and related costs
Restructuring Cost and Reserve [Line Items]
Balance at December 31, 2016	1,097
Restructuring charges and adjustments	204
Cash payments	(1,219)
Balance at March 31, 2017	82	1,097	82
Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Balance at December 31, 2016	1,565
Restructuring charges and adjustments	2,353
Cash payments	(100)
Balance at March 31, 2017	$ 3,818	$ 1,565	$ 3,818

Commitments and Contingencies39

Commitments and Contingencies (Detail)	1 Months Ended		3 Months Ended
	May 31, 2017USD ($)	Aug. 31, 2010USD ($)	Mar. 31, 2017USD ($)drawterm	Jun. 30, 2016USD ($)
Shared Services Agreement
Initial term of lease			123 months
Number of terms lease can be extended | term			2
Renewal term option of lease			60 months
Annual base rent			$ 600,000
Rent free term			3 months
Yearly increases in base rent			3.00%
Tenant improvement allowance			$ 1,900,000
Number of draws taken on the additional improvement allowance | draw			0
Future Minimum Payments for Operating Leases
2017 (nine months)			$ 450,929
2,018			614,855
2,019			633,364
2,020			652,340
2021 and thereafter			4,565,888
Total			6,917,376
Commercialization award received		$ 10,300,000
Commercialization award term		3 years
Standby Letters of Credit
Shared Services Agreement
Initial amount of standby letter of credit			2,400,000	$ 2,400,000
Reduced amount of standby letter of credit if certain conditions are met			$ 800,000
Scenario, Forecast
Future Minimum Payments for Operating Leases
Consideration paid for settlement of lease	$ 3,800,000

Net Loss Per Share Attributab40

Net Loss Per Share Attributable to Common Stockholders - Computation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Net loss attributable to common stockholders—basic and diluted	$ 4,977	$ 6,571
Weighted-average number of common shares—basic and diluted (in shares)	20,850,494	20,830,555
Net loss per share attributable to common stockholders—basic and diluted (in USD per share)	$ (0.24)	$ (0.32)

Net Loss Per Share Attributab41

Net Loss Per Share Attributable to Common Stockholders - Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Potentially dilutive securities excluded from the computation of diluted weighted average common shares outstanding	1,611,321	1,915,709

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) - Scenario, Forecast $ in Millions	1 Months Ended
	May 31, 2017USD ($)
Subsequent Event [Line Items]
Consideration paid for settlement of lease	$ 3.8
Contingency term for lease termination	60 days
Period which customer must not file for bankruptcy	90 days