ChemoCentryx (CCXI) 10-Q 9 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 29, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Trading Symbol	CCXI
Entity Registrant Name	ChemoCentryx, Inc.
Entity Central Index Key	1,340,652
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		47,762,362

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 21,925	$ 12,823
Short-term investments	103,784	58,455
Accounts receivable	175
Prepaid expenses and other current assets	1,157	757
Total current assets	127,041	72,035
Property and equipment, net	858	949
Long-term investments	14,145	5,011
Other assets	230	160
Total assets	142,274	78,155
Current liabilities:
Accounts payable	513	675
Accrued liabilities	6,720	4,819
Deferred revenue	15,720
Total current liabilities	22,953	5,494
Non-current deferred revenue	59,660
Other non-current liabilities	131	154
Total liabilities	82,744	5,648
Preferred stock:
Preferred stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding;
Common stock, $0.001 par value, 200,000,000 shares authorized at June 30, 2016 and December 31, 2015; 47,755,595 shares and 44,185,506 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively.	48	44
Additional paid-in capital	351,740	339,615
Note receivable	(16)	(16)
Accumulated other comprehensive income (loss)	80	(40)
Accumulated deficit	(292,322)	(267,096)
Total stockholders' equity	59,530	72,507
Total liabilities and stockholders' equity	$ 142,274	$ 78,155

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	47,755,595	44,185,506
Common stock, shares outstanding	47,755,595	44,185,506

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
Collaboration and license revenue	$ 2,620		$ 2,620
Grant revenue	175		175
Total revenue	2,795		2,795
Operating expenses:
Research and development	9,062	$ 8,602	20,307	$ 17,022
General and administrative	3,877	3,576	7,961	7,265
Total operating expenses	12,939	12,178	28,268	24,287
Loss from operations	(10,144)	(12,178)	(25,473)	(24,287)
Other income (expense):
Interest income	161	100	247	203
Total other income, net	161	100	247	203
Net loss	$ (9,983)	$ (12,078)	$ (25,226)	$ (24,084)
Basic and diluted net loss per common share	$ (0.22)	$ (0.28)	$ (0.56)	$ (0.55)
Shares used to compute basic and diluted net loss per common share	45,785	43,842	45,031	43,672

Condensed Consolidated Stateme5

Condensed Consolidated Statement of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net loss	$ (9,983)	$ (12,078)	$ (25,226)	$ (24,084)
Unrealized gain on available-for-sale securities	64	3	120	81
Comprehensive loss	$ (9,919)	$ (12,075)	$ (25,106)	$ (24,003)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities
Net loss	$ (25,226)	$ (24,084)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	173	259
Stock-based compensation	4,641	4,752
Noncash interest expense, net	(124)	625
Changes in assets and liabilities:
Accounts receivable	(175)
Prepaids and other current assets	(400)	72
Other assets	(70)
Accounts payable	(162)	280
Deferred revenue	75,380
Other liabilities	1,878	(3,241)
Net cash provided by (used in) operating activities	55,915	(21,337)
Investing activities
Purchases of property and equipment, net	(82)	(118)
Purchases of investments	(95,907)	(18,351)
Maturities of investments	41,688	29,700
Sales of investments	0	4,051
Net cash provided by (used in) investing activities	(54,301)	15,282
Financing activities
Proceeds from issuance of common stock	7,000
Proceeds from exercise of stock options and employee stock purchase plan	488	1,550
Net cash provided by financing activities	7,488	1,550
Net increase (decrease) in cash and cash equivalents	9,102	(4,505)
Cash and cash equivalents at beginning of period	12,823	16,075
Cash and cash equivalents at end of period	$ 21,925	$ 11,570

Description of Business

Description of Business	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. Description of Business ChemoCentryx, Inc. (the Company) commenced operations in 1997. The Company is a clinical-stage biopharmaceutical company focused on discovering, developing and commercializing orally-administered therapeutics to treat orphan and rare diseases, autoimmune diseases, inflammatory disorders and cancer. The Company’s principal operations are in the United States and it operates in one segment. Unaudited Interim Financial Information The financial information filed is unaudited. The Condensed Consolidated Financial Statements included in this report reflect all adjustments (consisting only of normal recurring adjustments) that the Company considers necessary for the fair statement of the results of operations for the interim periods covered and of the financial condition of the Company at the date of the interim balance sheet. The December 31, 2015 Condensed Consolidated Balance Sheet was derived from audited financial statements, but does not include all disclosures required by generally accepted accounting principles in the United States of America (GAAP). The results for interim periods are not necessarily indicative of the results for the entire year or any other interim period. The Condensed Consolidated Financial Statements should be read in conjunction with the Company’s financial statements and the notes thereto included in the Company’s annual report on Form 10-K for the year ended December 31, 2015 filed with the Securities and Exchange Commission (SEC) on March 14, 2016.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, the period of performance, identification of deliverables and evaluation of milestones with respect to collaborations. Concentration of Credit Risk The Company invests in a variety of financial instruments and, by its policy, limits the amount of credit exposure with any one issuer, industry or geographic area. Accounts receivable are typically unsecured and are concentrated in the pharmaceutical industry and government sector. Accordingly, the Company may be exposed to credit risk generally associated with pharmaceutical companies and government funded entities. The Company has not historically experienced any significant losses. At June 30, 2016, accounts receivable consisted of amounts due from the U.S. Food and Drug Administration under an Orphan Products Development grant and the Company believes that the associated credit risks are not significant. Net Loss Per Share Basic net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss attributable to common stockholders by the sum of the weighted-average number of common shares outstanding and dilutive common stock equivalent shares outstanding for the period. The Company’s potentially dilutive common stock equivalent shares, which include incremental common shares issuable upon (i) the exercise of outstanding stock options and warrants, (ii) vesting of restricted stock units (RSUs), and (iii) the purchase from contributions to the 2012 Employee Stock Purchase Plan (the ESPP), (calculated based on the treasury stock method), are only included in the calculation of diluted net loss per share when their effect is dilutive. For the six months ended June 30, 2016 and 2015, the following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: Six Months Ended 2016 2015 Options to purchase common stock, including purchases from contributions to ESPP 9,352,432 7,954,304 Restricted stock units 347,111 58,975 Warrants to purchase common stock 150,000 150,000 9,849,543 8,163,279 Revenue Recognition The Company enters into corporate collaborations under which the Company may obtain upfront license fees, research and development funding, contingent milestones and royalty payments. The Company’s deliverables under these arrangements typically consist of intellectual property rights and research and development services. The Company evaluates whether the delivered elements under these arrangements have value to the collaboration partners on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered item exists. If the Company determines that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. A delivered item or items that do not qualify as a separate unit of accounting within the arrangement shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. A delivered item or items that do not have stand-alone value to the Company’s collaboration partner shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. For a combined unit of accounting, non-refundable upfront fees and milestones are recognized in a manner consistent with the final deliverable, which has generally been ratably over the period of performance obligation. Contingency payments (received upon the achievement of certain events by the Company’s collaborators) and milestone payments (received upon the achievement of certain events by the Company) are non-refundable and recognized as revenues over the period of the collaboration arrangement. This typically results in a portion of the payments being recognized at the date the contingency or milestone is achieved, which portion is equal to the applicable percentage of the performance period that has elapsed at the date of achievement, and the balance being recognized over the remaining performance period of the agreement. In certain situations, the Company may receive contingent payments after the end of the Company’s period of continued involvement. In such circumstances, the Company would recognize the full amount of the contingent revenues when the contingency is achieved. Contingency and milestones payments, when recognized as revenue, are classified as collaboration and license revenues in the Condensed Consolidated Statements of Operations. Revenue from government and private agency grants are recognized as the related research and development expenses are incurred and to the extent that funding is approved. Comprehensive Loss Comprehensive loss comprises net loss and other comprehensive income. For the periods presented other comprehensive income consists of unrealized gains on the Company’s available-for-sale securities. For the three and six months ended June 30, 2016, there were no sales of investments, and therefore there were no reclassifications. For the same periods ended June 30, 2015, amounts reclassified from accumulated other income to net income for unrealized gains (losses) on available-for-sale securities were not significant, and were recorded as part of other income (expense), net in the Condensed Consolidated Statements of Operations. Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Boards (FASB) issued Accounting Standards Updates (ASU) No. 2014-15 (Subtopic 205-40)—Presentation of Financial Statements—Going Concern: Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15) which provides guidance about management’s responsibility to evaluate whether or not there is substantial doubt about the Company’s ability to continue as a going concern and to provide related footnote disclosure. ASU 2014-15 is effective for the Company the year ending December 31, 2016. Early application is permitted. The adoption of this standard is not expected to have an impact on its financial statements. In May 2015, the FASB issued a comprehensive new standard on revenue from contracts with customers. The standard’s core principle is that a reporting entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. On July 9, 2015, the FASB voted to delay the effective date of the new standard by one year. The standard would become effective for the Company beginning in the first quarter of 2018. Early application would be permitted in 2017. Entities would have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company is currently evaluating the impact of its adoption of this standard on its financial statements. In February 2016, the FASB issued a new standard that requires all lessees recognize the assets and liabilities that arise from leases on the balance sheet and disclose qualitative and quantitative information about its leasing arrangements. The new standard will be effective for the Company on January 1, 2019. The Company is currently evaluating the impact of this standard on its financial statements. In March 2016, FASB issued guidance that changes the accounting for certain aspects of share-based payments to employees. The guidance requires the recognition of the income tax effects of awards in the income statement when the awards vest or are settled, thus eliminating additional paid in capital pools. The guidance also allows for the employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. In addition, the guidance allows for a policy election to account for forfeitures as they occur rather than on an estimated basis. The guidance is effective in 2017 with early adoption permitted. The Company is currently evaluating the impact of this guidance on its financial statements.

Cash Equivalents and Investment

Cash Equivalents and Investments	6 Months Ended
	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Cash Equivalents and Investments	3. Cash Equivalents and Investments The amortized cost and fair value of cash equivalents and investments at June 30, 2016 and December 31, 2015 were as follows (in thousands): June 30, 2016 Amortized Cost Gross Unrealized Fair Value Gains Losses Money market fund $ 21,715 $ — $ — $ 21,715 U.S. treasury securities 21,133 59 — 21,192 Government-sponsored agencies 16,964 5 — 16,969 Commercial paper 20,323 — — 20,323 Corporate debt securities 59,429 22 (6 ) 59,445 Total available-for-sale securities $ 139,564 $ 86 $ (6 ) $ 139,644 Classified as: Cash equivalents $ 21,715 Short-term investments 103,784 Long-term investments 14,145 Total available-for-sale securities $ 139,644 December 31, 2015 Amortized Cost Gross Unrealized Fair Value Gains Losses Money market fund $ 11,340 — — $ 11,340 U.S. treasury securities 14,027 1 (2 ) 14,026 Government-sponsored agencies 30,959 — (25 ) 30,934 Commercial paper 3,992 — — 3,992 Corporate debt securities 14,528 — (14 ) 14,514 Total available-for-sale securities $ 74,846 $ 1 $ (41 ) $ 74,806 Classified as: Cash equivalents $ 11,340 Short-term investments 58,455 Long-term investments 5,011 Total available-for-sale securities $ 74,806 Cash equivalents in the tables above exclude cash of $0.2 million and $1.5 million as of June 30, 2016 and December 31, 2015, respectively. All available-for-sale securities held as of June 30, 2016 had contractual maturities of less than two years. There have been no significant realized gains or losses on available-for-sale securities for the periods presented. No available-for-sale securities held as of June 30, 2016 have been in a continuous unrealized loss position for more than 12 months. As of June 30, 2016, unrealized losses on available-for-sale investments are not attributed to credit risk and are considered to be temporary. The Company believes that it is more-likely-than-not that investments in an unrealized loss position will be held until maturity or the recovery of the cost basis of the investment. The Company believes it has no other-than-temporary impairments on its securities because it does not intend to sell these securities and it believes it is not more likely than not that it will be required to sell these securities before the recovery of their amortized cost basis. To date, the Company has not recorded any impairment charges on marketable securities related to other-than-temporary declines in market value.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The Company determines the fair value of financial assets and liabilities using three levels of inputs as follows: Level 1—Inputs which include quoted prices in active markets for identical assets and liabilities. Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements are as follows as of June 30, 2016 and December 31, 2015 (in thousands): June 30, 2016 Description Level 1 Level 2 Level 3 Total Money market fund $ 21,715 $ — $ — 21,715 U.S. treasury securities — 21,192 — 21,192 Government-sponsored agencies — 16,969 — 16,969 Commercial paper — 20,323 — 20,323 Corporate debt securities — 59,445 — 59,445 Total assets $ 21,715 $ 117,929 $ — $ 139,644 December 31, 2015 Description Level 1 Level 2 Level 3 Total Money market fund $ 11,340 $ — $ — $ 11,340 U.S. treasury securities — 14,026 — 14,026 Government-sponsored agencies — 30,934 — 30,934 Commercial paper — 3,992 — 3,992 Corporate debt securities — 14,514 — 14,514 Total assets $ 11,340 $ 63,466 $ — $ 74,806 During the six months ended June 30, 2016, there were no transfers between Level 1 and Level 2 financial assets. When the Company uses observable market prices for identical securities that are traded in less active markets, the Company classifies its marketable debt instruments as Level 2. When observable market prices for identical securities are not available, the Company prices its marketable debt instruments using non-binding market consensus prices that are corroborated with observable market data; quoted market prices for similar instruments; or pricing models, such as a discounted cash flow model, with all significant inputs derived from or corroborated with observable market data. Non-binding market consensus prices are based on the proprietary valuation models of pricing providers or brokers. These valuation models incorporate a number of inputs, including non-binding and binding broker quotes; observable market prices for identical or similar securities; and the internal assumptions of pricing providers or brokers that use observable market inputs and, to a lesser degree, unobservable market inputs. The Company corroborates non-binding market consensus prices with observable market data using statistical models when observable market data exists. The discounted cash flow model uses observable market inputs, such as LIBOR-based yield curves, currency spot and forward rates, and credit ratings.

Accrued Liabilities

Accrued Liabilities	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
Accrued Liabilities	5. Accrued Liabilities Accrued liabilities consist of the following (in thousands): June 30, December 31, Research and development related $ 4,472 $ 2,223 Compensation related 1,491 1,908 Consulting and Professional Services 461 454 Other 296 234 $ 6,720 $ 4,819

Related-Party Transactions

Related-Party Transactions	6 Months Ended
	Jun. 30, 2016
Related Party Transactions [Abstract]
Related-Party Transactions	6. Related-Party Transactions Bio-Techne Bio-Techne Corporation, formerly Techne Corporation, is one of the Company’s principal stockholders. In connection with the Company’s initial public offering (IPO) in February 2012, Bio-Techne received a warrant with a ten-year term to purchase 150,000 shares of the Company’s common stock at an exercise price per share equal to $20.00 per share, or 200% of the IPO price of its common stock, which was outstanding as of June 30, 2016. The Company had an accounts payable balance due to Bio-Techne for the purchases of research materials of $15,000 and zero as of June 30, 2016 and December 31, 2015, respectively.

Collaboration and License Agree

Collaboration and License Agreement	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration and License Agreement	7. Collaboration and License Agreement In May, 2016, the Company entered into an exclusive collaboration and license agreement with Vifor (International) Ltd., (Vifor) pursuant to which the Company granted Vifor exclusive rights to commercialize CCX168 in Europe and certain other markets (the CCX168 Agreement). CCX168 is the Company’s lead drug candidate for the treatment of patients with anti-neutrophil cytoplasmic auto-antibody associated vasculitis and other rare diseases. The Company retained control of ongoing and future development of CCX168 (other than country-specific development in the licensed territories) and all commercialization rights to CCX168 in the United States and other countries not licensed to Vifor. The CCX168 Agreement also provides Vifor with an exclusive option to negotiate during 2016 a worldwide license agreement for one of the Company’s other drug candidates, CCX140, an orally administered inhibitor of the chemokine receptor known as CCR2. In connection with the CCX168 Agreement, the Company received a non-refundable upfront payment of $85.0 million, comprising $60.0 million in cash and $25.0 million in the form of an equity investment to purchase 3,333,333 shares of the Company’s common stock at a price of $7.50 per share. The $85.0 million upfront consideration has been allocated as follows: • $7.0 million for the issuance of 3,333,333 shares of the Company’s common stock valued at $2.10 per share, the closing stock price on the effective date of the agreement, May 9, 2016. • $12.5 million, which may be credited against an upfront fee payable by Vifor, should the parties enter into a worldwide license agreement for CCX140. The amount creditable decreases ratably over time and will fully expire in the fourth quarter of 2016. As of June 30, 2016, the Company recorded the $12.5 million non-refundable, potential advance payment as noncurrent deferred revenue on the Company’s Condensed Consolidated Balance Sheets. • The remaining upfront consideration of $65.5 million will be recognized over the estimated period of performance under the CCX168 Agreement, which approximates 4.2 years. The deliverables under the CCX168 Agreement consist of intellectual property licenses, development and regulatory services for the submission of the Marketing Authorization Application (MAA). The Company considered the provisions of the revenue recognition multiple-element arrangement guidance and concluded that the license and the development and regulatory activities for the submission of the MAA do not have stand-alone value because the rights conveyed to do not permit Vifor to perform all efforts necessary to use the Company’s technology to bring the compound through development and, upon regulatory approval, commercialization of the compound. Accordingly, the Company combined these deliverables and allocated the remaining upfront consideration of $65.5 million into a single unit of accounting. For the three and six months ended June 30, 2016, the Company recognized $2.6 million under the CCX168 Agreement. Upon achievement of certain regulatory and commercial milestones with CCX168, the Company will receive additional payments of up to $510.0 million under the CCX168 Agreement. In addition, the Company will receive royalties, with rates ranging between the teens and mid-twenties, on future potential net sales of CCX168 by Vifor in the licensed territories. The Company determined that future contingent payments related to regulatory milestones meet the definition of a substantive milestone under the accounting guidance. Accordingly, revenue for the achievement of these milestones will be recognized in the period when the milestone is achieved. The Company will be eligible to receive contingent payments related to commercial milestones based on the performance of Vifor and these payments are not considered to be milestones under the accounting guidance. These contingent commercial milestone payments will be included in the allocation of arrangement consideration if and when achieved, resulting in an accounting treatment similar to the upfront payment. As of June 30, 2016, the Company has not received any milestone payments under the CCX168 Agreement. The Company expects to recognize royalty revenue in the period of sale of the related product, based on the underlying contract terms.

Government Grant

Government Grant	6 Months Ended
	Jun. 30, 2016
Text Block [Abstract]
Government Grant	8. Government Grant In April 2016, the Company was awarded an Orphan Products Development grant by the U.S. Food and Drug Administration in the amount of $500,000 to support the clinical development of CCX168. The term of the grant expires in May 2017. During the six months ended June 30, 2016, the Company recognized $175,000 of grant revenue and such amount was recorded as accounts receivable as of June 30, 2016.

Equity Incentive Plans

Equity Incentive Plans	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity Incentive Plans	9. Equity Incentive Plans Stock Options During the six months ended June 30, 2016, the Company had the following option activities under its equity incentive plans: Outstanding Options Available Shares Weighted Average Weighted Aggregate Balance at December 31, 2015 2,157,641 7,847,449 $ 8.52 Shares authorized 1,750,000 Granted (1) (2,033,410 ) 1,706,600 3.42 Exercised — (107,500 ) 2.05 Forfeited and expired 114,225 (114,225 ) 7.51 Balance at June 30, 2016 1,988,456 9,332,324 $ 7.68 6.95 $ 1,853,141 (1) The difference between shares granted in the number of shares available for grant and outstanding options represents the RSUs granted for the period. Stock-based Compensation Total stock-based compensation expense was $2.3 million and $4.6 million during the three and six months ended June 30, 2016, respectively, and $2.4 million and $4.8 million, respectively, during the same period ended June 30, 2015. As of June 30, 2016, $11.8 million, $1.1 million, and $0.1 million of total unrecognized compensation expenses associated with outstanding stock options, unvested RSUs, and the ESPP, net of estimated forfeitures, were expected to be recognized over a weighted-average period of 2.57, 2.01, and 0.38 years, respectively.

Summary of Significant Accoun16

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from these estimates. On an ongoing basis, management evaluates its estimates including, but not limited to, those related to revenue recognition, the period of performance, identification of deliverables and evaluation of milestones with respect to collaborations.
Concentration of Credit Risk	Concentration of Credit Risk The Company invests in a variety of financial instruments and, by its policy, limits the amount of credit exposure with any one issuer, industry or geographic area. Accounts receivable are typically unsecured and are concentrated in the pharmaceutical industry and government sector. Accordingly, the Company may be exposed to credit risk generally associated with pharmaceutical companies and government funded entities. The Company has not historically experienced any significant losses. At June 30, 2016, accounts receivable consisted of amounts due from the U.S. Food and Drug Administration under an Orphan Products Development grant and the Company believes that the associated credit risks are not significant.
Net Loss Per Share	Net Loss Per Share Basic net loss per common share is computed by dividing net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is computed by dividing net loss attributable to common stockholders by the sum of the weighted-average number of common shares outstanding and dilutive common stock equivalent shares outstanding for the period. The Company’s potentially dilutive common stock equivalent shares, which include incremental common shares issuable upon (i) the exercise of outstanding stock options and warrants, (ii) vesting of restricted stock units (RSUs), and (iii) the purchase from contributions to the 2012 Employee Stock Purchase Plan (the ESPP), (calculated based on the treasury stock method), are only included in the calculation of diluted net loss per share when their effect is dilutive. For the six months ended June 30, 2016 and 2015, the following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: Six Months Ended 2016 2015 Options to purchase common stock, including purchases from contributions to ESPP 9,352,432 7,954,304 Restricted stock units 347,111 58,975 Warrants to purchase common stock 150,000 150,000 9,849,543 8,163,279
Revenue Recognition	Revenue Recognition The Company enters into corporate collaborations under which the Company may obtain upfront license fees, research and development funding, contingent milestones and royalty payments. The Company’s deliverables under these arrangements typically consist of intellectual property rights and research and development services. The Company evaluates whether the delivered elements under these arrangements have value to the collaboration partners on a stand-alone basis and whether objective and reliable evidence of fair value of the undelivered item exists. If the Company determines that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. A delivered item or items that do not qualify as a separate unit of accounting within the arrangement shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. A delivered item or items that do not have stand-alone value to the Company’s collaboration partner shall be combined with the other applicable undelivered items within the arrangement. The allocation of arrangement consideration and the recognition of revenue then shall be determined for those combined deliverables as a single unit of accounting. For a combined unit of accounting, non-refundable upfront fees and milestones are recognized in a manner consistent with the final deliverable, which has generally been ratably over the period of performance obligation. Contingency payments (received upon the achievement of certain events by the Company’s collaborators) and milestone payments (received upon the achievement of certain events by the Company) are non-refundable and recognized as revenues over the period of the collaboration arrangement. This typically results in a portion of the payments being recognized at the date the contingency or milestone is achieved, which portion is equal to the applicable percentage of the performance period that has elapsed at the date of achievement, and the balance being recognized over the remaining performance period of the agreement. In certain situations, the Company may receive contingent payments after the end of the Company’s period of continued involvement. In such circumstances, the Company would recognize the full amount of the contingent revenues when the contingency is achieved. Contingency and milestones payments, when recognized as revenue, are classified as collaboration and license revenues in the Condensed Consolidated Statements of Operations. Revenue from government and private agency grants are recognized as the related research and development expenses are incurred and to the extent that funding is approved.
Comprehensive Loss	Comprehensive Loss Comprehensive loss comprises net loss and other comprehensive income. For the periods presented other comprehensive income consists of unrealized gains on the Company’s available-for-sale securities. For the three and six months ended June 30, 2016, there were no sales of investments, and therefore there were no reclassifications. For the same periods ended June 30, 2015, amounts reclassified from accumulated other income to net income for unrealized gains (losses) on available-for-sale securities were not significant, and were recorded as part of other income (expense), net in the Condensed Consolidated Statements of Operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2014, the Financial Accounting Standards Boards (FASB) issued Accounting Standards Updates (ASU) No. 2014-15 (Subtopic 205-40)—Presentation of Financial Statements—Going Concern: Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (ASU 2014-15) which provides guidance about management’s responsibility to evaluate whether or not there is substantial doubt about the Company’s ability to continue as a going concern and to provide related footnote disclosure. ASU 2014-15 is effective for the Company the year ending December 31, 2016. Early application is permitted. The adoption of this standard is not expected to have an impact on its financial statements. In May 2015, the FASB issued a comprehensive new standard on revenue from contracts with customers. The standard’s core principle is that a reporting entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. On July 9, 2015, the FASB voted to delay the effective date of the new standard by one year. The standard would become effective for the Company beginning in the first quarter of 2018. Early application would be permitted in 2017. Entities would have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company is currently evaluating the impact of its adoption of this standard on its financial statements. In February 2016, the FASB issued a new standard that requires all lessees recognize the assets and liabilities that arise from leases on the balance sheet and disclose qualitative and quantitative information about its leasing arrangements. The new standard will be effective for the Company on January 1, 2019. The Company is currently evaluating the impact of this standard on its financial statements. In March 2016, FASB issued guidance that changes the accounting for certain aspects of share-based payments to employees. The guidance requires the recognition of the income tax effects of awards in the income statement when the awards vest or are settled, thus eliminating additional paid in capital pools. The guidance also allows for the employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. In addition, the guidance allows for a policy election to account for forfeitures as they occur rather than on an estimated basis. The guidance is effective in 2017 with early adoption permitted. The Company is currently evaluating the impact of this guidance on its financial statements.
Fair Value of Financial Assets and Liabilities	The Company determines the fair value of financial assets and liabilities using three levels of inputs as follows: Level 1—Inputs which include quoted prices in active markets for identical assets and liabilities. Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
Market Prices for Identical Securities	When the Company uses observable market prices for identical securities that are traded in less active markets, the Company classifies its marketable debt instruments as Level 2. When observable market prices for identical securities are not available, the Company prices its marketable debt instruments using non-binding market consensus prices that are corroborated with observable market data; quoted market prices for similar instruments; or pricing models, such as a discounted cash flow model, with all significant inputs derived from or corroborated with observable market data. Non-binding market consensus prices are based on the proprietary valuation models of pricing providers or brokers. These valuation models incorporate a number of inputs, including non-binding and binding broker quotes; observable market prices for identical or similar securities; and the internal assumptions of pricing providers or brokers that use observable market inputs and, to a lesser degree, unobservable market inputs. The Company corroborates non-binding market consensus prices with observable market data using statistical models when observable market data exists. The discounted cash flow model uses observable market inputs, such as LIBOR-based yield curves, currency spot and forward rates, and credit ratings.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share Due to Anti-Dilutive Effect	For the six months ended June 30, 2016 and 2015, the following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect: Six Months Ended 2016 2015 Options to purchase common stock, including purchases from contributions to ESPP 9,352,432 7,954,304 Restricted stock units 347,111 58,975 Warrants to purchase common stock 150,000 150,000 9,849,543 8,163,279

Cash Equivalents and Investme18

Cash Equivalents and Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Amortized Cost and Fair Value of Cash Equivalents and Investments	The amortized cost and fair value of cash equivalents and investments at June 30, 2016 and December 31, 2015 were as follows (in thousands): June 30, 2016 Amortized Cost Gross Unrealized Fair Value Gains Losses Money market fund $ 21,715 $ — $ — $ 21,715 U.S. treasury securities 21,133 59 — 21,192 Government-sponsored agencies 16,964 5 — 16,969 Commercial paper 20,323 — — 20,323 Corporate debt securities 59,429 22 (6 ) 59,445 Total available-for-sale securities $ 139,564 $ 86 $ (6 ) $ 139,644 Classified as: Cash equivalents $ 21,715 Short-term investments 103,784 Long-term investments 14,145 Total available-for-sale securities $ 139,644 December 31, 2015 Amortized Cost Gross Unrealized Fair Value Gains Losses Money market fund $ 11,340 — — $ 11,340 U.S. treasury securities 14,027 1 (2 ) 14,026 Government-sponsored agencies 30,959 — (25 ) 30,934 Commercial paper 3,992 — — 3,992 Corporate debt securities 14,528 — (14 ) 14,514 Total available-for-sale securities $ 74,846 $ 1 $ (41 ) $ 74,806 Classified as: Cash equivalents $ 11,340 Short-term investments 58,455 Long-term investments 5,011 Total available-for-sale securities $ 74,806

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements of Company's Financial Assets and Liabilities	The Company’s financial assets and liabilities subject to fair value measurements on a recurring basis and the level of inputs used in such measurements are as follows as of June 30, 2016 and December 31, 2015 (in thousands): June 30, 2016 Description Level 1 Level 2 Level 3 Total Money market fund $ 21,715 $ — $ — 21,715 U.S. treasury securities — 21,192 — 21,192 Government-sponsored agencies — 16,969 — 16,969 Commercial paper — 20,323 — 20,323 Corporate debt securities — 59,445 — 59,445 Total assets $ 21,715 $ 117,929 $ — $ 139,644 December 31, 2015 Description Level 1 Level 2 Level 3 Total Money market fund $ 11,340 $ — $ — $ 11,340 U.S. treasury securities — 14,026 — 14,026 Government-sponsored agencies — 30,934 — 30,934 Commercial paper — 3,992 — 3,992 Corporate debt securities — 14,514 — 14,514 Total assets $ 11,340 $ 63,466 $ — $ 74,806

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2016
Payables and Accruals [Abstract]
Accrued Liabilities	Accrued liabilities consist of the following (in thousands): June 30, December 31, Research and development related $ 4,472 $ 2,223 Compensation related 1,491 1,908 Consulting and Professional Services 461 454 Other 296 234 $ 6,720 $ 4,819

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Option Activities under Its Equity Incentive Plans	During the six months ended June 30, 2016, the Company had the following option activities under its equity incentive plans: Outstanding Options Available Shares Weighted Average Weighted Aggregate Balance at December 31, 2015 2,157,641 7,847,449 $ 8.52 Shares authorized 1,750,000 Granted (1) (2,033,410 ) 1,706,600 3.42 Exercised — (107,500 ) 2.05 Forfeited and expired 114,225 (114,225 ) 7.51 Balance at June 30, 2016 1,988,456 9,332,324 $ 7.68 6.95 $ 1,853,141 (1) The difference between shares granted in the number of shares available for grant and outstanding options represents the RSUs granted for the period.

Description of Business - Addit

Description of Business - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2016Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segment	1

Summary of Significant Accoun23

Summary of Significant Accounting Policies - Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss per Share Due to Anti-Dilutive Effect (Detail) - shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	9,849,543	8,163,279
Options to Purchase Common Stock, Including Purchases from Contributions to ESPP [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	9,352,432	7,954,304
Unvested Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	347,111	58,975
Warrants to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	150,000	150,000

Summary of Significant Accoun24

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015
Accounting Policies [Abstract]
Amounts reclassified from accumulated other income to net income for unrealized gains (losses) on available-for-sale securities	$ 0	$ 0
Sales of investments	$ 0	$ 0	$ 4,051,000

Cash Equivalents and Investme25

Cash Equivalents and Investments - Amortized Cost and Fair Value of Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 139,564	$ 74,846
Gross Unrealized Gains	86	1
Gross Unrealized Losses	(6)	(41)
Available-for-sale Securities	139,644	74,806
Money Market Fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,715	11,340
Available-for-sale Securities	21,715	11,340
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,133	14,027
Gross Unrealized Gains	59	1
Gross Unrealized Losses		(2)
Available-for-sale Securities	21,192	14,026
Government-Sponsored Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,964	30,959
Gross Unrealized Gains	5
Gross Unrealized Losses		(25)
Available-for-sale Securities	16,969	30,934
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,323	3,992
Available-for-sale Securities	20,323	3,992
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	59,429	14,528
Gross Unrealized Gains	22
Gross Unrealized Losses	(6)	(14)
Available-for-sale Securities	$ 59,445	$ 14,514

Cash Equivalents and Investme26

Cash Equivalents and Investments - Amortized Cost and Fair Value of Cash Equivalents and Investments 2 (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Cash and Cash Equivalents [Abstract]
Cash equivalents	$ 21,715	$ 11,340
Short-term investments	103,784	58,455
Long-term investments	14,145	5,011
Available-for-sale Securities	$ 139,644	$ 74,806

Cash Equivalents and Investme27

Cash Equivalents and Investments - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2016USD ($)Investment	Dec. 31, 2015USD ($)
Cash and Cash Equivalents [Abstract]
Maturity period available-for-sale securities	Less than two years
Significant realized gains or losses on available-for-sale securities	$ 0
Cash	$ 200,000	$ 1,500,000
Number of available-for-sale securities in a continuous unrealized loss position for more than 12 months | Investment	0

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Measurements of Company's Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 139,644	$ 74,806
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	139,644	74,806
Money Market Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,715	11,340
Money Market Fund [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,715	11,340
U.S. Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,192	14,026
U.S. Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,192	14,026
Government-Sponsored Agencies [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	16,969	30,934
Government-Sponsored Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	16,969	30,934
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	20,323	3,992
Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	20,323	3,992
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	59,445	14,514
Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	59,445	14,514
Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,715	11,340
Level 1 [Member] | Money Market Fund [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,715	11,340
Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	117,929	63,466
Level 2 [Member] | U.S. Treasury Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	21,192	14,026
Level 2 [Member] | Government-Sponsored Agencies [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	16,969	30,934
Level 2 [Member] | Commercial Paper [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	20,323	3,992
Level 2 [Member] | Corporate Debt Securities [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 59,445	$ 14,514

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	Jun. 30, 2016USD ($)
Fair Value Disclosures [Abstract]
Transfers from Level 1 to Level 2 financial assets	$ 0
Transfers from Level 2 to Level 1 financial assets	$ 0

Accrued Liabilities - Accrued L

Accrued Liabilities - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Research and development related	$ 4,472	$ 2,223
Compensation related	1,491	1,908
Consulting and Professional Services	461	454
Other	296	234
Accrued liabilities	$ 6,720	$ 4,819

Related-Party Transactions - Ad

Related-Party Transactions - Additional Information (Detail) - USD ($)	1 Months Ended
	Feb. 29, 2012	Jun. 30, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Accounts payable balance		$ 513,000	$ 675,000
Bio-Techne Corporation [Member]
Related Party Transaction [Line Items]
Warrant contractual term	10 years
Purchase of warrant common stock	150,000
Warrants to purchase common stock, exercise price	$ 20
Warrant common stock exercise price rate	200.00%
Accounts payable balance		$ 15,000	$ 0

Collaboration and License Agr32

Collaboration and License Agreement - Additional Information (Detail) - USD ($)	May 09, 2016	May 31, 2016	Jun. 30, 2016	Jun. 30, 2016
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Non refundable upfront payments received		$ 85,000,000
Non refundable upfront payment received in cash		60,000,000
Non refundable upfront payment received in equity investment		$ 25,000,000
Share price of common stock in equity investment		$ 7.50
Non refundable upfront payment received in equity investment, shares		3,333,333
Non refundable upfront payments allocated for issuance of common stock	$ 7,000,000
Issuance of common stock, per share value	$ 2.10
Creditable upfront fee for CCX140 Agreement				$ 12,500,000
Non refundable upfront payments allocated for development and regulatory activities.				$ 65,500,000
Estimated period of performance				4 years 2 months 12 days
Collaboration and license revenue			$ 2,620,000	$ 2,620,000
Milestone payments received				0
Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Potential milestone payments receivable				$ 510,000,000

Government Grant - Additional I

Government Grant - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended	6 Months Ended
	Apr. 30, 2016	Jun. 30, 2016	Jun. 30, 2016
Government Grants [Abstract]
Orphan products development grant	$ 500,000
Grant revenue		$ 175,000	$ 175,000
Amount of grant receivable		$ 175,000	$ 175,000

Equity Incentive Plans - Option

Equity Incentive Plans - Option Activities under Its Equity Incentive Plans (Detail)	6 Months Ended
	Jun. 30, 2016USD ($)$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares Available for Grant, Outstanding Beginning Balance	2,157,641
Available for Grant, Shares authorized	1,750,000
Shares Available for Grant, Granted	(2,033,410)
Shares Available for Grant, Exercised	0
Shares Available for Grant, Forfeited and expired	114,225
Shares Available for Grant, Outstanding Ending Balance	1,988,456
Shares, Options Outstanding, Beginning Balance	7,847,449
Shares, Options Outstanding, Granted	1,706,600
Shares, Options Outstanding, Exercised	(107,500)
Shares, Options Outstanding, Forfeited and expired	(114,225)
Shares, Options Outstanding, Ending Balance	9,332,324
Weighted Average Exercise Price, Options Outstanding, Beginning Balance | $ / shares	$ 8.52
Weighted Average Exercise Price, Options Outstanding, Granted | $ / shares	3.42
Weighted Average Exercise Price, Options Outstanding, Exercised | $ / shares	2.05
Weighted Average Exercise Price, Options Outstanding, Forfeited and expired | $ / shares	7.51
Weighted Average Exercise Price, Options Outstanding, Ending Balance | $ / shares	$ 7.68
Options Outstanding, Weighted Average Remaining Contractual Term	6 years 11 months 12 days
Aggregate Intrinsic Value, Outstanding, Ending Balance | $	$ 1,853,141

Equity Incentive Plans - Additi

Equity Incentive Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 2,300	$ 2,400	$ 4,641	$ 4,752
ESPP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	100		$ 100
Total unrecognized compensation expenses, weighted-average period			4 months 17 days
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	$ 11,800		$ 11,800
Total unrecognized compensation expenses, weighted-average period	2 years 6 months 26 days
Unvested Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expenses, weighted-average period	2 years 4 days
Unrecognized compensation expenses	$ 1,100		$ 1,100