Mirati Therapeutics (MRTX) 10-Q 4 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Aug. 01, 2016
Document and Entity Information
Entity Registrant Name	Mirati Therapeutics, Inc.
Entity Central Index Key	1,576,263
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		19,924,005
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 24,542	$ 49,493
Short-term investments	66,771	72,834
Other current assets	1,726	3,075
Total current assets	93,039	125,402
Property and equipment, net	558	614
Other long-term assets	2,396	2,001
Total assets	95,993	128,017
Current liabilities
Accounts payable and accrued liabilities	13,790	9,798
Total current liabilities	13,790	9,798
Other liability	24	43
Total liabilities	13,814	9,841
Stockholders’ equity
Preferred stock, $0.001 par value, 10,000,000 shares authorized; none issued and outstanding at both June 30, 2016 and December 31, 2015	0	0
Common stock, $0.001 par value; 100,000,000 shares authorized; 19,924,005 and 19,282,935 issued and outstanding at June 30, 2016 and December 31, 2015, respectively	20	19
Additional paid-in capital	423,149	415,232
Accumulated other comprehensive income	9,618	9,558
Accumulated deficit	(350,608)	(306,633)
Total stockholders’ equity	82,179	118,176
Total liabilities and stockholders’ equity	$ 95,993	$ 128,017

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	19,924,005	19,282,935
Common stock, shares outstanding (in shares)	19,924,005	19,282,935

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Expenses
Research and development	$ 18,441	$ 11,276	$ 36,429	$ 19,483
General and administrative	3,786	4,240	7,916	8,019
Total operating expenses	22,227	15,516	44,345	27,502
Loss from operations	(22,227)	(15,516)	(44,345)	(27,502)
Other income, net	166	70	370	116
Net loss	(22,061)	(15,446)	(43,975)	(27,386)
Unrealized gain (loss) on available-for-sale investments	33	(9)	60	(4)
Comprehensive loss	$ (22,028)	$ (15,455)	$ (43,915)	$ (27,390)
Basic and diluted net loss per share	$ (1.11)	$ (0.95)	$ (2.24)	$ (1.74)
Weighted average number of shares used in computing net loss per share, basic and diluted	19,912,938	16,235,261	19,646,889	15,727,891

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net loss	$ (43,975)	$ (27,386)
Non-cash adjustments reconciling net loss to operating cash flows:
Depreciation	101	100
Amortization of premium on investments	25	251
Share-based compensation expense	5,326	5,108
Changes in operating assets and liabilities:
Other current assets	1,349	1,338
Other long-term assets	395	(38)
Accounts payable, accrued liabilities and other long-term liabilities	3,973	1,737
Cash flows used for operating activities	(33,596)	(18,814)
Investing activities:
Purchases of short-term investments	(49,680)	(41,024)
Disposal and maturities of short-term investments	55,778	17,980
Purchases of property and equipment	(45)	(297)
Cash flows provided (used) by investing activities	6,053	(23,341)
Financing activities:
Proceeds from sale of common stock, net	0	48,361
Proceeds from exercise of warrants and common stock options	2,355	330
Proceeds from stock issuances under employee stock purchase plan	237	250
Cash flows provided by financing activities	2,592	48,941
(Decrease) increase in cash and cash equivalents	(24,951)	6,786
Cash and cash equivalents, beginning of period	49,493	6,593
Cash and cash equivalents, end of period	$ 24,542	$ 13,379

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Mirati Therapeutics, Inc. ("Mirati" or the "Company") is a clinical-stage biopharmaceutical company focused on developing a pipeline of targeted oncology products. The Company focuses its development programs on drugs intended to treat specific genetic and epigenetic drivers of cancer in selected subsets of cancer patients with unmet needs. The Company's common stock has been listed on the NASDAQ Capital Market since July 15, 2013 under the ticker symbol "MRTX." The Company has a wholly owned subsidiary in Canada, MethylGene, Inc. (“MethylGene”).

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The unaudited condensed consolidated financial statements contained in this Quarterly Report on Form 10-Q have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") and, therefore, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been omitted. In the opinion of management, the information reflects all adjustments necessary to make the results of operations for the interim periods a fair statement of such operations. All such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for the full year. The consolidated balance sheet at December 31, 2015 has been derived from the audited consolidated financial statements at that date, but does not include all information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2015 . Use of Estimates The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. Estimates and assumptions are reviewed quarterly. Any revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected. Cash, Cash Equivalents and Short-term Investments Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less. Investments with an original maturity of more than ninety days are considered short-term investments and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary. Such investments are carried at fair value, and the unrealized gains and losses are reported as a component of accumulated other comprehensive income (loss) in stockholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis. Concentration of Credit Risk The Company invests its excess cash in accordance with its investment policy. The Company's investments are comprised primarily of commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. The Company mitigates credit risk by maintaining a diversified portfolio and limiting the amount of investment exposure as to institution, maturity and investment type. Financial instruments that potentially subject the Company to significant credit risk consist principally of cash equivalents and short-term investments. Foreign Currency Transactions Foreign currency transactions are initially recorded by the Company using the exchange rates prevailing at the date of the transaction. At the balance sheet date, monetary assets and liabilities denominated in foreign currencies are translated at the period-end rates of exchange. Non-monetary assets and liabilities are translated at the historical exchange rates. Exchange gains and losses arising from the translation of foreign currency items are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss. Segment Reporting Operating segments are components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker for purposes of making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States. Net loss per share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s stock option and warrant agreements. The following table presents the weighted average number of potentially dilutive securities not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Common stock options 255,551 554,689 330,450 470,934 Common stock warrants 352,441 1,792,069 611,223 1,765,511 Total 607,992 2,346,758 941,673 2,236,445

Recent Accounting Pronouncement

Recent Accounting Pronouncements	6 Months Ended
	Jun. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position or results of operations upon adoption. In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718). The new guidance changes the accounting and simplifies various aspects of the accounting for share-based payments to employees. The guidance allows for a policy election to account for forfeitures as they occur or based on an estimated number of awards that are expected to vest. ASU 2016-09 is effective for annual periods beginning after December 15, 2016, with early adoption permitted. The Company is currently evaluating the impact the standard will have on its consolidated financial statements, but does not believe the adoption of this standard will have a material impact on its financial position, results of operations or related financial statement disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). Under the new guidance, lessees are required to recognize most lease assets and lease liabilities on their balance sheets and record expenses on their income statements in a manner similar to current accounting. The new guidance is effective for fiscal years beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the impact that this guidance will have on its consolidated financial statements and related financial statement disclosures. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The new guidance enhances the reporting model for financial instruments and includes amendments to address aspects of recognition, measurement, presentation and disclosure. The update to the standard is effective for public companies for interim and annual periods beginning after December 15, 2017. The Company does not believe the adoption of this standard will have a material impact on its financial position, results of operations or related financial statement disclosures. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes, to simplify the presentation of deferred taxes. This amendment requires that all deferred tax assets and liabilities, along with any related valuation allowances, be classified as noncurrent on the balance sheet. ASU 2015-17 is effective for annual and interim reporting periods ending after December 15, 2016. Early adoption is permitted, and the new guidance is and may be applied either prospectively or retrospectively. We have adopted this guidance prospectively as of December 31, 2015. Therefore, prior periods have not been adjusted to reflect this adoption. In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter; early adoption is permitted. The Company has not elected to early adopt and is currently evaluating the potential changes from this ASU to its future financial reporting and disclosures. In May 2014, the FASB issued Accounting Standard Update ("ASU") 2014-09, Revenue from Contracts with Customers (Topic 606), which will replace numerous requirements in U.S. GAAP, including industry-specific requirements, and provide companies with a single revenue recognition model for recognizing revenue from contracts with customers. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In August 2015, the FASB approved a proposal to defer the effective date of the guidance until annual and interim reporting periods beginning after December 15, 2017. The Company is currently evaluating the impact that this standard will have on its consolidated financial statements.

Investments

Investments	6 Months Ended
	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The following tables summarize our short-term investments (dollars in thousands): As of June 30, 2016 Maturity Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Corporate debt securities 1 year or less $ 27,184 $ — $ — $ 27,184 Commercial paper 1 year or less 39,488 99 — 39,587 $ 66,672 $ 99 $ — $ 66,771 As of December 31, 2015 Maturity Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Corporate debt securities 1 year or less $ 27,644 $ — $ (22 ) $ 27,622 Commercial paper 1 year or less 45,158 54 — 45,212 $ 72,802 $ 54 $ (22 ) $ 72,834 Unrealized gains and losses on available-for-sale securities are included as a component of comprehensive loss. At June 30, 2016 , the Company did not have any securities in material unrealized loss positions. The Company reviews its investments to identify and evaluate investments that have an indication of possible other-than-temporary impairment. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition and near-term prospects of the investee, and the Company’s intent and ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in market value. The Company does not intend to sell any investments prior to recovery of their amortized cost basis for any investments in an unrealized loss position.

Fair value measurements

Fair value measurements	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1 or 2 within the fair value hierarchy as described in the accounting standards for fair value measurements. The authoritative guidance for fair value measurements defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or the most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The guidance prioritizes the inputs used in measuring fair value into the following hierarchy: • Level 1- Quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2- Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable; and • Level 3- Unobservable inputs in which little or no market activity exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing. The following tables summarize the assets and liabilities measured at fair value on a recurring basis (in thousands): June 30, 2016 Total Level 1 Level 2 Level 3 Assets Cash and cash equivalents: Cash $ 3,570 $ 3,570 $ — $ — Money market funds 19,472 19,472 — — Corporate debt securities 1,500 — 1,500 — Total cash and cash equivalents 24,542 23,042 1,500 — Short-term investments: Corporate debt securities 27,184 — 27,184 — Commercial paper 39,587 — 39,587 — Total short-term investments 66,771 — 66,771 — Total $ 91,313 $ 23,042 $ 68,271 $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets Cash and cash equivalents: Cash $ 875 $ 875 $ — $ — Money market funds 18,875 18,875 — — Corporate debt securities 6,749 — 6,749 — Commercial paper 22,994 — 22,994 — Total cash and cash equivalents 49,493 19,750 29,743 — Short-term investments: Corporate debt securities 27,622 — 27,622 — Commercial paper 45,212 — 45,212 — Total short-term investments 72,834 — 72,834 — Total $ 122,327 $ 19,750 $ 102,577 $ — The Company’s investments in Level 1 assets are valued based on publicly available quoted market prices for identical securities as of June 30, 2016 and December 31, 2015 . The Company determines the fair value of Level 2 related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. There were no transfers between fair value measurement levels during the three and six months ended June 30, 2016 or the year ended December 31, 2015 .

Other current assets and other

Other current assets and other long-term assets	6 Months Ended
	Jun. 30, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other current assets and other long-term assets	Other current assets and other long-term assets Other current assets consisted of the following (in thousands): June 30, December 31, 2016 2015 Prepaid expenses $ 928 $ 2,287 Security deposits and other receivables 516 551 Interest receivable 282 237 $ 1,726 $ 3,075 The other long-term assets balance consisted of $2.4 million and $2.0 million in deposits paid in conjunction with the Company's research and development activities as of June 30, 2016 and December 31, 2015 , respectively.

Property and equipment, net

Property and equipment, net	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Property and equipment, net	Property and equipment, net Property and equipment consisted of the following (in thousands): June 30, December 31, 2016 2015 Computer equipment $ 329 $ 329 Office and other equipment 301 256 Laboratory equipment 425 425 Leasehold improvements 51 51 Gross property and equipment 1,106 1,061 Less: Accumulated depreciation (548 ) (447 ) Net property and equipment $ 558 $ 614 The Company incurred immaterial depreciation expense for the three months ended June 30, 2016 and 2015 and $0.1 million for both the six months ended June 30, 2016 and 2015 .

Accounts payable and accrued li

Accounts payable and accrued liabilities	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
Accounts payable and accrued liabilities	Accounts payable and accrued liabilities Accounts payable and accrued liabilities consisted of the following (in thousands): June 30, December 31, 2016 2015 Accounts payable $ 4,445 $ 2,104 Accrued expenses 7,002 5,311 Accrued compensation and benefits 2,307 2,352 Other current liabilities 36 31 $ 13,790 $ 9,798

Warrants

Warrants	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Warrants	Warrants As of June 30, 2016 the following warrants for common stock were issued and outstanding: Issue date Expiration date Exercise price Number of warrants outstanding November 21, 2012 November 21, 2017 $ 7.86 695,383 During the three months ended June 30, 2016, no warrants were exercised. During the six months ended June 30, 2016 , warrants for 419,244 shares of the Company's common stock were exercised via cashless exercises and 313,756 shares were exercised for cash generating proceeds of $2.1 million for the six months ended June 30, 2016 . The Company issued a total of 603,545 shares of common stock for the same period. During the three and six months ended June 30, 2015 , warrants for 179,296 and 192,570 shares of the Company's common stock were exercised via cashless exercises and the Company issued a total of 139,503 and 148,818 shares of common stock, respectively. Stockholders' Equity Share-based Compensation Total share-based compensation expense by operating statement classification is presented below (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Research and development expense $ 1,478 $ 931 $ 2,936 $ 1,739 General and administrative expense 810 1,861 2,390 3,369 $ 2,288 $ 2,792 $ 5,326 $ 5,108 During the three months ended June 30, 2016 and 2015 , 1,836 and 4,750 shares were issued pursuant to stock option exercises, respectively, generating immaterial net proceeds. During the six months ended June 30, 2016 and 2015 , 22,132 and 26,916 shares were issued pursuant to stock option exercises generating net proceeds of $0.2 million and $0.3 million , respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
Leases [Abstract]
Commitments and Contingencies	Commitments and Contingencies On June 24, 2014, the Company entered into a lease agreement for approximately 18,000 square feet of completed office and laboratory space located in San Diego, California. The office space under the lease is the Company's new corporate headquarters, replacing the previous facilities. The lease commenced in phases, 2,300 square feet of space which commenced on July 1, 2014 at an initial monthly rent of $5,900 per month and 15,600 square feet of space which commenced on March 27, 2015 at an initial monthly rent of $18,200 per month. The leased property is subject to a 3% annual rent increase following availability. In addition to such base monthly rent, the Company is obligated to pay certain customary amounts for its share of operating expenses and facility amenities. The lease will expire on January 31, 2018. Future minimum payments required under the lease are summarized as follows (in thousands): Year Ending December 31: 2016 $ 148 2017 305 2018 25 Total minimum lease payments $ 478

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stockholders' Equity	Warrants As of June 30, 2016 the following warrants for common stock were issued and outstanding: Issue date Expiration date Exercise price Number of warrants outstanding November 21, 2012 November 21, 2017 $ 7.86 695,383 During the three months ended June 30, 2016, no warrants were exercised. During the six months ended June 30, 2016 , warrants for 419,244 shares of the Company's common stock were exercised via cashless exercises and 313,756 shares were exercised for cash generating proceeds of $2.1 million for the six months ended June 30, 2016 . The Company issued a total of 603,545 shares of common stock for the same period. During the three and six months ended June 30, 2015 , warrants for 179,296 and 192,570 shares of the Company's common stock were exercised via cashless exercises and the Company issued a total of 139,503 and 148,818 shares of common stock, respectively. Stockholders' Equity Share-based Compensation Total share-based compensation expense by operating statement classification is presented below (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Research and development expense $ 1,478 $ 931 $ 2,936 $ 1,739 General and administrative expense 810 1,861 2,390 3,369 $ 2,288 $ 2,792 $ 5,326 $ 5,108 During the three months ended June 30, 2016 and 2015 , 1,836 and 4,750 shares were issued pursuant to stock option exercises, respectively, generating immaterial net proceeds. During the six months ended June 30, 2016 and 2015 , 22,132 and 26,916 shares were issued pursuant to stock option exercises generating net proceeds of $0.2 million and $0.3 million , respectively.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The unaudited condensed consolidated financial statements contained in this Quarterly Report on Form 10-Q have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") and, therefore, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been omitted. In the opinion of management, the information reflects all adjustments necessary to make the results of operations for the interim periods a fair statement of such operations. All such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for the full year. The consolidated balance sheet at December 31, 2015 has been derived from the audited consolidated financial statements at that date, but does not include all information and footnotes required by U.S. generally accepted accounting principles for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2015 .
Use of Estimates	Use of Estimates The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. Estimates and assumptions are reviewed quarterly. Any revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.
Cash and Cash Equivalents	Cash, Cash Equivalents and Short-term Investments Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less.
Short-term Investments	Investments with an original maturity of more than ninety days are considered short-term investments and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary.
Concentration of Credit Risk	Concentration of Credit Risk The Company invests its excess cash in accordance with its investment policy. The Company's investments are comprised primarily of commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. The Company mitigates credit risk by maintaining a diversified portfolio and limiting the amount of investment exposure as to institution, maturity and investment type. Financial instruments that potentially subject the Company to significant credit risk consist principally of cash equivalents and short-term investments.
Foreign Currency Transactions	Foreign Currency Transactions Foreign currency transactions are initially recorded by the Company using the exchange rates prevailing at the date of the transaction. At the balance sheet date, monetary assets and liabilities denominated in foreign currencies are translated at the period-end rates of exchange. Non-monetary assets and liabilities are translated at the historical exchange rates. Exchange gains and losses arising from the translation of foreign currency items are included in other income (expense), net in the condensed consolidated statements of operations and comprehensive loss.
Segment Reporting	Segment Reporting Operating segments are components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker for purposes of making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States.
Net loss per share	Net loss per share Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s stock option and warrant agreements.

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Schedule of potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive	The following table presents the weighted average number of potentially dilutive securities not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities: Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Common stock options 255,551 554,689 330,450 470,934 Common stock warrants 352,441 1,792,069 611,223 1,765,511 Total 607,992 2,346,758 941,673 2,236,445

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following tables summarize our short-term investments (dollars in thousands): As of June 30, 2016 Maturity Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Corporate debt securities 1 year or less $ 27,184 $ — $ — $ 27,184 Commercial paper 1 year or less 39,488 99 — 39,587 $ 66,672 $ 99 $ — $ 66,771 As of December 31, 2015 Maturity Amortized cost Gross unrealized gains Gross unrealized losses Estimated fair value Corporate debt securities 1 year or less $ 27,644 $ — $ (22 ) $ 27,622 Commercial paper 1 year or less 45,158 54 — 45,212 $ 72,802 $ 54 $ (22 ) $ 72,834

Fair value measurements (Tables

Fair value measurements (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Schedule of assets and liabilities that are measured at fair value on a recurring basis	The following tables summarize the assets and liabilities measured at fair value on a recurring basis (in thousands): June 30, 2016 Total Level 1 Level 2 Level 3 Assets Cash and cash equivalents: Cash $ 3,570 $ 3,570 $ — $ — Money market funds 19,472 19,472 — — Corporate debt securities 1,500 — 1,500 — Total cash and cash equivalents 24,542 23,042 1,500 — Short-term investments: Corporate debt securities 27,184 — 27,184 — Commercial paper 39,587 — 39,587 — Total short-term investments 66,771 — 66,771 — Total $ 91,313 $ 23,042 $ 68,271 $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets Cash and cash equivalents: Cash $ 875 $ 875 $ — $ — Money market funds 18,875 18,875 — — Corporate debt securities 6,749 — 6,749 — Commercial paper 22,994 — 22,994 — Total cash and cash equivalents 49,493 19,750 29,743 — Short-term investments: Corporate debt securities 27,622 — 27,622 — Commercial paper 45,212 — 45,212 — Total short-term investments 72,834 — 72,834 — Total $ 122,327 $ 19,750 $ 102,577 $ —

Other current assets (Tables)

Other current assets (Tables)	6 Months Ended
	Jun. 30, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of other current assets	Other current assets consisted of the following (in thousands): June 30, December 31, 2016 2015 Prepaid expenses $ 928 $ 2,287 Security deposits and other receivables 516 551 Interest receivable 282 237 $ 1,726 $ 3,075

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	6 Months Ended
	Jun. 30, 2016
Property, Plant and Equipment [Abstract]
Schedule of property and equipment	Property and equipment consisted of the following (in thousands): June 30, December 31, 2016 2015 Computer equipment $ 329 $ 329 Office and other equipment 301 256 Laboratory equipment 425 425 Leasehold improvements 51 51 Gross property and equipment 1,106 1,061 Less: Accumulated depreciation (548 ) (447 ) Net property and equipment $ 558 $ 614

Accounts payable and accrued 23

Accounts payable and accrued liabilities (Tables)	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
Schedule of accounts payable and accrued liabilities	Accounts payable and accrued liabilities consisted of the following (in thousands): June 30, December 31, 2016 2015 Accounts payable $ 4,445 $ 2,104 Accrued expenses 7,002 5,311 Accrued compensation and benefits 2,307 2,352 Other current liabilities 36 31 $ 13,790 $ 9,798

Warrants (Tables)

Warrants (Tables)	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Schedule of Warrants Issued and Outstanding	As of June 30, 2016 the following warrants for common stock were issued and outstanding: Issue date Expiration date Exercise price Number of warrants outstanding November 21, 2012 November 21, 2017 $ 7.86 695,383

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2016
Leases [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum payments required under the lease are summarized as follows (in thousands): Year Ending December 31: 2016 $ 148 2017 305 2018 25 Total minimum lease payments $ 478

Stock-based compensation (Table

Stock-based compensation (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Employee Service Share-based Compensation Allocation	Total share-based compensation expense by operating statement classification is presented below (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Research and development expense $ 1,478 $ 931 $ 2,936 $ 1,739 General and administrative expense 810 1,861 2,390 3,369 $ 2,288 $ 2,792 $ 5,326 $ 5,108

Summary of Significant Accoun27

Summary of Significant Accounting Policies - Narrative (Details)	6 Months Ended
	Jun. 30, 2016segment
Marketable Securities
Minimum original maturity period of marketable securities	90 days
Number of operating segments	1

Summary of Significant Accoun28

Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	607,992	2,346,758	941,673	2,236,445
Common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	255,551	554,689	330,450	470,934
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	352,441	1,792,069	611,223	1,765,511

Investments (Details)

Investments (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Amortized cost	$ 66,672	$ 72,802
Available-for-sale, Gross unrealized gains	99	54
Available-for-sale, Gross unrealized losses	0	(22)
Available-for-sale, Estimated fair value	$ 66,771	$ 72,834
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, maximum maturity period	1 year	1 year
Available-for-sale, Amortized cost	$ 27,184	$ 27,644
Available-for-sale, Gross unrealized gains	0	0
Available-for-sale, Gross unrealized losses	0	(22)
Available-for-sale, Estimated fair value	$ 27,184	$ 27,622
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, maximum maturity period	1 year	1 year
Available-for-sale, Amortized cost	$ 39,488	$ 45,158
Available-for-sale, Gross unrealized gains	99	54
Available-for-sale, Gross unrealized losses	0	0
Available-for-sale, Estimated fair value	$ 39,587	$ 45,212

(Details)

(Details) - Recurring basis - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 24,542	$ 49,493
Short-term investments	66,771	72,834
Total	91,313	122,327
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	27,184	27,622
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	39,587	45,212
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,570	875
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	19,472	18,875
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,500	6,749
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		22,994
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	23,042	19,750
Short-term investments	0	0
Total	23,042	19,750
Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 1 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	3,570	875
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	19,472	18,875
Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,500	29,743
Short-term investments	66,771	72,834
Total	68,271	102,577
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	27,184	27,622
Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	39,587	45,212
Level 2 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	1,500	6,749
Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		22,994
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Short-term investments	0	0
Total	0	0
Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Level 3 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0	0
Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents		$ 0

Other current assets (Details)

Other current assets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 928	$ 2,287
Security deposits and other receivables	516	551
Interest receivable	282	237
Other current assets	1,726	3,075
Deposits paid for research and development	$ 2,400	$ 2,000

Property and Equipment, net (De

Property and Equipment, net (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 1,106		$ 1,061
Less: Accumulated depreciation	(548)		(447)
Net property and equipment	558		614
Depreciation	101	$ 100
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	329		329
Office and other equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	301		256
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	425		425
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, Gross	$ 51		$ 51

Accounts payable and accrued 33

Accounts payable and accrued liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 4,445	$ 2,104
Accrued expenses	7,002	5,311
Accrued compensation and benefits	2,307	2,352
Other current liabilities	36	31
Total accounts payable and accrued liabilities	$ 13,790	$ 9,798

Warrants (Details)

Warrants (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Class of Warrant or Right [Line Items]
Warrants exercised via cashless exercises	179,296	419,244	192,570
Warrants exercised for cash		313,756
Cash proceeds generated from exercise of warrants		$ 2.1
Shares of common stock issued from exercise of warrants	139,503	603,545	148,818
November 21, 2012 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (in dollars per share)		$ 7.86
Number of warrants outstanding		695,383

Commitments and Contingencies N

Commitments and Contingencies Narrative (Details) - Building	6 Months Ended
	Jun. 30, 2016USD ($)ft²	Jun. 24, 2014ft²
Operating Leased Assets [Line Items]
Square feet of space		18,000
Annual rent increase (Percentage)	3.00%
Lease Agreement Phase One
Operating Leased Assets [Line Items]
Square feet of space	2,300
Minimum monthly rental expense | $	$ 5,900
Lease Agreement Phase Two
Operating Leased Assets [Line Items]
Square feet of space	15,600
Minimum monthly rental expense | $	$ 18,200

Commitments and Contingencies F

Commitments and Contingencies Future Minimum Payments (Details) $ in Thousands	Jun. 30, 2016USD ($)
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,016	$ 148
2,017	305
2,018	25
Total minimum lease payments	$ 478

Stock-based compensation (Detai

Stock-based compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 2,288	$ 2,792	$ 5,326	$ 5,108
Shares issued	1,836	4,750	22,132	26,916
Cash received from exercise of options	$ 200			$ 300
Research and development expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	1,478	$ 931	$ 2,936	1,739
General and administrative expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 810	$ 1,861	$ 2,390	$ 3,369