Cidara Therapeutics (CDTX) 10-Q 11 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 31, 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	CDTX
Entity Registrant Name	Cidara Therapeutics, Inc.
Entity Central Index Key	1,610,618
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		13,906,654

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 29,271	$ 62,562
Short-term investments	57,818	44,952
Prepaid expenses and other current assets	1,142	704
Total current assets	88,231	108,218
Property and equipment, net	1,603	1,684
Other assets	190	72
Total assets	90,024	109,974
Current liabilities:
Accounts payable	1,517	3,095
Accrued liabilities	2,003	1,415
Accrued compensation and benefits	1,605	1,464
Total current liabilities	5,125	5,974
Other long-term liabilities	90	88
Total liabilities	5,215	6,062
Commitments and contingencies (Note 7)
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized and no shares issued or outstanding at June 30, 2016 and December 31, 2015, respectively
Common stock, $0.0001 par value; 200,000,000 shares authorized at June 30, 2016 and December 31, 2015; 13,994,378 and 13,900,576 shares issued and outstanding, respectively, at June 30, 2016; 13,942,520 and 13,786,285 shares issued and outstanding, respectively, at December 31, 2015	1	1
Additional paid-in capital	151,853	149,416
Accumulated other comprehensive loss	(4)	(8)
Accumulated deficit	(67,041)	(45,497)
Total stockholders' equity	84,809	103,912
Total liabilities and stockholders' equity	$ 90,024	$ 109,974

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
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	$ 0.0001	$ 0.0001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	13,994,378	13,942,520
Common stock, shares outstanding	13,900,576	13,786,285

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating expenses:
Research and development	$ 8,471	$ 4,210	$ 15,660	$ 9,145
General and administrative	3,391	2,236	6,087	4,033
Total operating expenses	11,862	6,446	21,747	13,178
Loss from operations	(11,862)	(6,446)	(21,747)	(13,178)
Other income (expense):
Interest income (expense), net	107	32	203	27
Total other income (expense)	107	32	203	27
Net loss	(11,755)	(6,414)	(21,544)	(13,151)
Other comprehensive income:
Unrealized gain on short-term investments	(2)		4
Comprehensive loss	$ (11,757)	$ (6,414)	$ (21,540)	$ (13,151)
Basic and diluted net loss per share	$ (0.85)	$ (0.59)	$ (1.56)	$ (2.16)
Weighted average shares outstanding used to compute net loss per share, basic and diluted	13,871,938	10,957,150	13,839,864	6,075,134

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net loss	$ (21,544)	$ (13,151)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	369	189
Stock-based compensation	1,942	1,479
Amortization of discount or premium on short-term investments	(80)
Amortization of debt issue costs		11
Deferred rent	1	(7)
Changes in assets and liabilities:
Prepaid expenses and other current assets	(439)	(520)
Accounts payable and accrued liabilities	(925)	(260)
Accrued compensation	435	341
Other assets	(117)
Net cash used in operating activities	(20,358)	(11,918)
Investing activities:
Purchases of short-term investments	(47,782)
Maturities of short-term investments	35,000
Purchases of property and equipment	(217)	(157)
Net cash used in investing activities	(12,999)	(157)
Financing activities:
Proceeds from initial public offering, net of offering costs		69,543
Proceeds from exercise of stock options	66	116
Net cash provided by financing activities	66	111,580
Net (decrease) increase in cash and cash equivalents	(33,291)	99,505
Cash and cash equivalents at beginning of period	62,562	22,796
Cash and cash equivalents at end of period	29,271	122,301
Non-cash investing activities:
Property and equipment acquired but not yet paid	70
Non-cash financing activities:
Vesting of early exercised stock options	135	192
Purchase of shares pursuant to Employee Stock Purchase Plan	$ 294
Deferred initial public offering costs incurred but not yet paid		13
Deferred initial public offering costs paid in 2014		233
Series B Convertible Preferred Stock
Financing activities:
Proceeds from issuance convertible preferred stock, net of offering costs		41,921
Non-cash financing activities:
Conversion convertible preferred stock to common upon initial public offering		41,921
Series A Convertible Preferred Stock
Non-cash financing activities:
Conversion convertible preferred stock to common upon initial public offering		$ 32,548

The Company and Basis of Presen

The Company and Basis of Presentation	6 Months Ended
	Jun. 30, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Company and Basis of Presentation	1. THE COMPANY AND BASIS OF PRESENTATION Description of Business Cidara Therapeutics, Inc., or the Company, was originally incorporated in Delaware in December 2012 as K2 Therapeutics, Inc., and its name was changed to Cidara Therapeutics, Inc. in July 2014. The Company is a biotechnology company focused on the discovery, development and commercialization of novel anti-infectives. The Company’s initial product portfolio is comprised of proprietary product candidates for the treatment of serious fungal infections. In March 2016, the Company formed a wholly-owned subsidiary, Cidara Therapeutics UK Limited, in England for the purpose of developing its product candidates in Europe. Basis of Presentation The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has experienced net losses and negative cash flows from operating activities since its inception. At June 30, 2016, the Company had an accumulated deficit of $67.0 million. The Company expects to continue to incur net losses into the foreseeable future. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. The Company plans to continue to fund its losses from operations and capital funding needs through debt and equity financing or through collaborations or partnerships with other companies. Debt or equity financing or collaborations and partnerships with other companies may not be available on a timely basis on terms acceptable to the Company, or at all. If the Company is not able to secure adequate additional funding, the Company may be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts, or to make reductions in spending, extend payment terms with suppliers, liquidate or grant rights to assets where possible, or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects. Unaudited Interim Financial Data —The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States, or GAAP, as found in the Accounting Standards Codification, or ASC, of the Financial Accounting Standards Board, or FASB. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These interim condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods ended June 30, 2016 and 2015. Basis of Consolidation —The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates —The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The Company evaluates its estimates and assumptions on an ongoing basis. The most significant estimates in the Company’s financial statements relate to certain accruals, including those related to preclinical and clinical activities, and the fair value of the Company’s common shares used to account for share-based compensation. Although the estimates are based on the Company’s knowledge of current events, practices of comparable companies, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Segment Information —Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment.

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 Cash and Cash Equivalents —The Company considers all securities purchased with a maturity of three months or less when acquired to be cash equivalents. Investments Available-for-Sale — Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in accumulated other comprehensive income (loss). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. The amortization of premiums and accretion of discounts is included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income (expense). The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. Securities with maturity dates of 12 months or less from the date of purchase (other than cash equivalents) are classified as short-term investments and securities with maturity dates of more than 12 months are classified as long-term investments. Concentration of Credit Risk —The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. Periodically, the Company maintains deposits in government insured financial institutions in excess of government insured limits. The Company invests its cash balances in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to significant credit risk. Patent Costs —The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses. Income Taxes —The Company follows FASB ASC 740 Income Taxes , or ASC 740, in reporting deferred income taxes. ASC 740 requires a company to recognize deferred tax liabilities and assets for expected future income tax consequences of events that have been recognized in the Company’s financial statements. Under this method, deferred tax assets and liabilities are determined based on temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates in the years in which the temporary differences are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions pursuant to ASC 740, which prescribes a recognition threshold and measurement process for financial statement recognition of uncertain tax positions taken or expected to be taken in a tax return. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes. Research and Development Costs —Research and development expenses consist of wages, benefits and stock-based compensation charges for research and development employees, scientific consultant fees, facilities and overhead expenses, laboratory supplies, manufacturing expenses, and preclinical and clinical trial costs. The Company accrues clinical trial expenses based on work performed which relies on estimates of total costs incurred based on patient enrollment, completion of studies or activities within studies, and other events. Costs incurred in purchasing technology assets and intellectual property are charged to research and development expense if the technology has not been conclusively proven to be feasible and has no alternative future use. Comprehensive Loss —Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources. The Company’s only component of other comprehensive loss is unrealized gains (losses) on short-term marketable securities. Comprehensive gains (losses) have been reflected in the condensed consolidated statements of operations and comprehensive loss for all periods presented. Stock-based Compensation —The Company accounts for stock-based compensation expense related to employee stock options, restricted stock grants, and employee stock purchase plan rights by estimating the fair value on the date of grant using the Black-Scholes option pricing model. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized ratably over the requisite service period of the awards, net of estimated forfeitures. The Company accounts for stock options granted to non-employees using the fair value approach. These option grants are subject to periodic revaluation over their vesting terms. Net Loss Per Share —Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for 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 dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of convertible preferred stock, unvested restricted common stock subject to repurchase, and options outstanding under the Company’s stock option plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding. The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): June 30, 2016 2015 Common stock options issued and outstanding 2,115,056 1,479,578 Common stock subject to repurchase 93,802 304,843 Total 2,208,858 1,784,421 Fair Value of Financial Instruments —The Company follows authoritative guidance with respect to fair value reporting issued by the FASB for financial assets and liabilities, which defines fair value, provides guidance for measuring fair value and requires certain disclosures. The guidance does not apply to measurements related to share-based payments. The guidance discusses valuation techniques, such as the market approach (comparable market prices), the income approach (present value of future income or cash flow), and the cost approach (cost to replace the service capacity of an asset or replacement cost). The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The Company’s financial instruments consist of cash and cash equivalents, marketable securities, prepaid expenses, accounts payable, and accrued liabilities. Fair value estimates of these instruments are made at a specific point in time based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore may not be determinable with precision. The carrying amount of cash and cash equivalents, prepaid expenses, accounts payable, and accrued liabilities are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. The fair value of marketable securities is based upon market prices quoted on the last day of the fiscal period or other observable market inputs. Recently Issued Accounting Standards —During 2016, the FASB issued ASU 2016-02, “Leases,” which requires that lease arrangements longer than 12 months result in an entity recognizing an asset and liability. The updated guidance is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently assessing the impact that this standard will have on its financial statements. During 2016, the FASB issued ASU 2016-09, "Compensation-Stock Compensation,” which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The updated guidance is effective for interim and annual periods beginning after December 15, 2016, and early adoption is permitted. The Company is currently assessing the impact that this standard will have on its financial statements.

Short-Term Investments

Short-Term Investments	6 Months Ended
	Jun. 30, 2016
Investments Debt And Equity Securities [Abstract]
Short-Term Investments	3. SHORT-TERM INVESTMENTS The following table summarizes the available-for-sale securities held at June 30, 2016 and December 31, 2015 (in thousands): As of June 30, 2016 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Certificates of deposit $ 36,500 $ - $ - $ 36,500 Commercial paper 21,322 2 (6 ) 21,318 Total $ 57,822 $ 2 $ (6 ) $ 57,818 As of December 31, 2015 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Certificates of deposit $ 20,000 $ - $ - $ 20,000 Commercial paper 24,960 - (8 ) 24,952 Total $ 44,960 $ - $ (8 ) $ 44,952 All available-for-sale securities held at June 30, 2016 and December 31, 2015 had maturities of less than one year.

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 follows ASC 820-10, Fair Value Measurements and Disclosures As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1 : Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 : Inputs, other than Level 1 inputs, that are observable either directly or indirectly; and Level 3 : Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The carrying amounts of the Company’s financial instruments, including cash and cash equivalents, prepaid expenses, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. At June 30, 2016 and December 31, 2015, the Company held certificates of deposit, which are valued at cost, and commercial paper, which is valued using observable market inputs including reported trades, broker/dealer quotes, bids and/or offers. None of the Company’s non-financial assets or liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. The following tables summarize the Company’s financial instruments measured at fair value on a recurring basis: TOTAL LEVEL 1 LEVEL 2 LEVEL 3 June 30, 2016 Assets: Money market funds $ 5,149 $ 5,149 $ - $ - Certificates of deposit included in cash and cash equivalents 24,000 - 24,000 - Certificates of deposit included in short-term investments 36,500 - 36,500 - Commercial paper 21,318 - 21,318 - Total assets at fair value $ 86,967 $ 5,149 $ 81,818 $ - December 31, 2015 Assets: Money market funds $ 12,353 $ 12,353 $ - $ - Certificates of deposit included in cash and cash equivalents 50,000 - 50,000 - Certificates of deposit included in short-term investments 20,000 - 20,000 - Commercial paper 24,952 - 24,952 - Total assets at fair value $ 107,305 $ 12,353 $ 94,952 $ -

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2016
Equity [Abstract]
Stockholders' Equity	5. STOCKHOLDERS’ EQUITY On February 10, 2015, the Company sold Series B convertible preferred stock, or Series B preferred, for gross proceeds of $42.0 million. On April 20, 2015, the Company completed its initial public offering, or IPO, whereby the Company sold 4,800,000 shares of common stock at a price of $16.00 per share. Proceeds from the IPO were approximately $69.3 million, net of underwriting discounts and commissions and offering costs. In connection with the IPO, the outstanding shares of the Company’s Series A convertible preferred stock, or Series A preferred, and Series B preferred automatically converted into 7,561,380 shares of common stock.

Stock Incentive Plans

Stock Incentive Plans	6 Months Ended
	Jun. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Incentive Plans	6. STOCK INCENTIVE PLANS 2015 Equity Incentive Plan In March 2015, the Company’s board of directors and stockholders approved and adopted the 2015 Equity Incentive Plan, or the 2015 EIP. Under the 2015 EIP, the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, and other awards to individuals who are employees, officers, directors, or consultants of the Company. Employee Stock Purchase Plan In March 2015, the Company’s board of directors and stockholders approved and adopted the 2015 Employee Stock Purchase Plan, or the ESPP. The ESPP allows substantially all employees to purchase the Company’s common stock through a payroll deduction at a price equal to 85% of the lower of the fair market value of the stock as of the beginning or the end of each purchase period. An employee’s payroll deductions under the ESPP are limited to 15% of the employee’s eligible compensation. Restricted Stock The Company permits exercise of certain stock options prior to vesting. Any such unvested shares are restricted and subject to repurchase by the Company until the conditions for vesting are met. At June 30, 2016 and December 31, 2015, the liabilities for the cash received from the early exercise of stock options were $206,000 and $341,000, respectively, and were classified in accrued liabilities on the balance sheet. The Company reduces the liability as the underlying shares vest in accordance with the vesting terms outlined in the stock option agreements which are generally 4 years. At June 30, 2016, 93,802 unvested shares were subject to repurchase by the Company. Stock Options The following table summarizes stock option activity during the six months ended June 30, 2016: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Total Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 1,437,583 $ 6.19 Options granted 699,275 10.04 Options exercised (21,802 ) 3.04 Outstanding at June 30, 2016 2,115,056 7.49 8.93 $ 6,811 Vested and expected to vest at June 30, 2016 2,115,056 7.49 8.93 $ 6,811 Exercisable at June 30, 2016 1,249,131 $ 5.92 8.55 $ 5,923 The intrinsic value of a stock option is the difference between the market price of the common stock at the measurement date and the exercise price of the option. Stock-based compensation expense recognized for restricted shares, stock options, and the ESPP has been reported in the statements of operations as follows (in thousands): Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Research and development $ 525 $ 494 $ 881 $ 936 General and administrative 584 346 1,061 543 Total $ 1,109 $ 840 $ 1,942 $ 1,479 The weighted-average grant date fair value of employee stock options granted by the Company during the six months ended June 30, 2016 was $6.89 per share. The total grant date fair value of employee stock options that vested during the six months ended June 30, 2016 was $1.8 million. As of June 30, 2016, total unrecognized share-based compensation expense related to unvested employee stock options of the Company was approximately $8.0 million. This unrecognized compensation cost is expected to be recognized over a weighted-average period of approximately 2.3 years. As of June 30, 2016, total unrecognized compensation expense related to the ESPP was approximately $0.7 million. This unrecognized compensation cost is expected to be recognized over approximately 1.9 years. Common Stock Reserved for Future Issuance Common stock reserved for future issuance is as follows: June 30, 2016 December 31, 2015 Stock options issued and outstanding 2,115,056 1,437,583 Authorized for future stock awards or option grants 1,646,821 1,788,396 Authorized for future issuance under employee stock purchase plan 335,373 226,004 Total 4,097,250 3,451,983

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	7. COMMITMENTS AND CONTINGENCIES Litigation —From time to time, the Company may be involved in various lawsuits, legal proceedings, or claims that arise in the ordinary course of business. Management believes there are no claims or actions pending against the Company as of June 30, 2016 which will have, individually or in the aggregate, a material adverse effect on its business, liquidity, financial position, or results of operations. Litigation, however, is subject to inherent uncertainties, and an adverse result in such matters may arise from time to time that may harm the Company’s business. Lease Obligations —In June 2014, the Company entered into an operating lease agreement for laboratory and office space in San Diego, California. Amendments for additional space were entered into in February 2015, March 2015, and August 2015. The lease expires in December 2018 with two individual two-year extensions. The lease is subject to charges for common area maintenance and other costs. Rent expense is being recorded on a straight-line basis over the life of the lease. Future minimum payments required under the lease as of June 30, 2016 for the years ended December 31 are as follows (in thousands): 2016 357 2017 725 2018 747 Total minimum lease payments $ 1,829 Rent expense was $360,000 and $215,000 for the six months ended June 30, 2016 and 2015, respectively. Contractual Obligations —The Company enters into contracts in the normal course of business with vendors for research and development activities, manufacturing, and professional services. These contracts generally provide for termination either on notice or within 30 days of notice.

Summary of Significant Accoun13

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The accompanying condensed consolidated financial statements have been prepared assuming the Company will continue as a going concern, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The Company has experienced net losses and negative cash flows from operating activities since its inception. At June 30, 2016, the Company had an accumulated deficit of $67.0 million. The Company expects to continue to incur net losses into the foreseeable future. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. The Company plans to continue to fund its losses from operations and capital funding needs through debt and equity financing or through collaborations or partnerships with other companies. Debt or equity financing or collaborations and partnerships with other companies may not be available on a timely basis on terms acceptable to the Company, or at all. If the Company is not able to secure adequate additional funding, the Company may be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts, or to make reductions in spending, extend payment terms with suppliers, liquidate or grant rights to assets where possible, or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects.
Unaudited Interim Financial Data	Unaudited Interim Financial Data —The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company in accordance with accounting principles generally accepted in the United States, or GAAP, as found in the Accounting Standards Codification, or ASC, of the Financial Accounting Standards Board, or FASB. Certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. These interim condensed consolidated financial statements, in the opinion of management, reflect all normal recurring adjustments necessary for a fair presentation of the Company’s financial position and results of operations for the interim periods ended June 30, 2016 and 2015.
Basis of Consolidation	Basis of Consolidation —The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany accounts and transactions have been eliminated in consolidation.
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 reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. The Company evaluates its estimates and assumptions on an ongoing basis. The most significant estimates in the Company’s financial statements relate to certain accruals, including those related to preclinical and clinical activities, and the fair value of the Company’s common shares used to account for share-based compensation. Although the estimates are based on the Company’s knowledge of current events, practices of comparable companies, and actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.
Segment Information	Segment Information —Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision maker, the Chief Executive Officer, in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business as one operating segment.
Cash and Cash Equivalents	Cash and Cash Equivalents —The Company considers all securities purchased with a maturity of three months or less when acquired to be cash equivalents.
Investments Available-for-Sale	Investments Available-for-Sale — Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in accumulated other comprehensive income (loss). The amortized cost of debt securities is adjusted for amortization of premiums and accretion of discounts to maturity. The amortization of premiums and accretion of discounts is included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income (expense). The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income. Securities with maturity dates of 12 months or less from the date of purchase (other than cash equivalents) are classified as short-term investments and securities with maturity dates of more than 12 months are classified as long-term investments.
Concentration of Credit Risk	Concentration of Credit Risk —The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. Periodically, the Company maintains deposits in government insured financial institutions in excess of government insured limits. The Company invests its cash balances in financial institutions that it believes have high credit quality and has not experienced any losses on such accounts and does not believe it is exposed to significant credit risk.
Patent Costs	Patent Costs —The Company expenses all costs as incurred in connection with patent applications (including direct application fees, and the legal and consulting expenses related to making such applications) and such costs are included in general and administrative expenses.
Income Taxes	Income Taxes —The Company follows FASB ASC 740 Income Taxes , or ASC 740, in reporting deferred income taxes. ASC 740 requires a company to recognize deferred tax liabilities and assets for expected future income tax consequences of events that have been recognized in the Company’s financial statements. Under this method, deferred tax assets and liabilities are determined based on temporary differences between financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates in the years in which the temporary differences are expected to reverse. Valuation allowances are provided if, based on the weight of available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company accounts for uncertain tax positions pursuant to ASC 740, which prescribes a recognition threshold and measurement process for financial statement recognition of uncertain tax positions taken or expected to be taken in a tax return. If the tax position meets this threshold, the benefit to be recognized is measured as the tax benefit having the highest likelihood of being realized upon ultimate settlement with the taxing authority. The Company recognizes interest accrued related to unrecognized tax benefits and penalties in the provision for income taxes.
Research and Development Costs	Research and Development Costs —Research and development expenses consist of wages, benefits and stock-based compensation charges for research and development employees, scientific consultant fees, facilities and overhead expenses, laboratory supplies, manufacturing expenses, and preclinical and clinical trial costs. The Company accrues clinical trial expenses based on work performed which relies on estimates of total costs incurred based on patient enrollment, completion of studies or activities within studies, and other events. Costs incurred in purchasing technology assets and intellectual property are charged to research and development expense if the technology has not been conclusively proven to be feasible and has no alternative future use.
Comprehensive Loss	Comprehensive Loss —Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources. The Company’s only component of other comprehensive loss is unrealized gains (losses) on short-term marketable securities. Comprehensive gains (losses) have been reflected in the condensed consolidated statements of operations and comprehensive loss for all periods presented.
Stock-based Compensation	Stock-based Compensation —The Company accounts for stock-based compensation expense related to employee stock options, restricted stock grants, and employee stock purchase plan rights by estimating the fair value on the date of grant using the Black-Scholes option pricing model. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized ratably over the requisite service period of the awards, net of estimated forfeitures. The Company accounts for stock options granted to non-employees using the fair value approach. These option grants are subject to periodic revaluation over their vesting terms.
Net Loss Per Share	Net Loss Per Share —Basic net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for 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 dilutive common stock equivalents outstanding for the period determined using the treasury-stock and if-converted methods. Dilutive common stock equivalents are comprised of convertible preferred stock, unvested restricted common stock subject to repurchase, and options outstanding under the Company’s stock option plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding. The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): June 30, 2016 2015 Common stock options issued and outstanding 2,115,056 1,479,578 Common stock subject to repurchase 93,802 304,843 Total 2,208,858 1,784,421
Fair Value of Financial Instruments	Fair Value of Financial Instruments —The Company follows authoritative guidance with respect to fair value reporting issued by the FASB for financial assets and liabilities, which defines fair value, provides guidance for measuring fair value and requires certain disclosures. The guidance does not apply to measurements related to share-based payments. The guidance discusses valuation techniques, such as the market approach (comparable market prices), the income approach (present value of future income or cash flow), and the cost approach (cost to replace the service capacity of an asset or replacement cost). The guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. The Company’s financial instruments consist of cash and cash equivalents, marketable securities, prepaid expenses, accounts payable, and accrued liabilities. Fair value estimates of these instruments are made at a specific point in time based on relevant market information. These estimates may be subjective in nature and involve uncertainties and matters of significant judgment and therefore may not be determinable with precision. The carrying amount of cash and cash equivalents, prepaid expenses, accounts payable, and accrued liabilities are generally considered to be representative of their respective fair values because of the short-term nature of those instruments. The fair value of marketable securities is based upon market prices quoted on the last day of the fiscal period or other observable market inputs.
Recently Issued Accounting Standards	Recently Issued Accounting Standards —During 2016, the FASB issued ASU 2016-02, “Leases,” which requires that lease arrangements longer than 12 months result in an entity recognizing an asset and liability. The updated guidance is effective for interim and annual periods beginning after December 15, 2018, and early adoption is permitted. The Company is currently assessing the impact that this standard will have on its financial statements. During 2016, the FASB issued ASU 2016-09, "Compensation-Stock Compensation,” which simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The updated guidance is effective for interim and annual periods beginning after December 15, 2016, and early adoption is permitted. The Company is currently assessing the impact that this standard will have on its financial statements.

Summary of Significant Accoun14

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Summary of Outstanding Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti-dilutive (in common stock equivalent shares): June 30, 2016 2015 Common stock options issued and outstanding 2,115,056 1,479,578 Common stock subject to repurchase 93,802 304,843 Total 2,208,858 1,784,421

Short-Term Investments (Tables)

Short-Term Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following table summarizes the available-for-sale securities held at June 30, 2016 and December 31, 2015 (in thousands): As of June 30, 2016 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Certificates of deposit $ 36,500 $ - $ - $ 36,500 Commercial paper 21,322 2 (6 ) 21,318 Total $ 57,822 $ 2 $ (6 ) $ 57,818 As of December 31, 2015 Amortized Cost Unrealized Gains Unrealized Losses Fair Value Certificates of deposit $ 20,000 $ - $ - $ 20,000 Commercial paper 24,960 - (8 ) 24,952 Total $ 44,960 $ - $ (8 ) $ 44,952

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Summary of Financial Instruments Measured at Fair Value on Recurring Basis	The following tables summarize the Company’s financial instruments measured at fair value on a recurring basis: TOTAL LEVEL 1 LEVEL 2 LEVEL 3 June 30, 2016 Assets: Money market funds $ 5,149 $ 5,149 $ - $ - Certificates of deposit included in cash and cash equivalents 24,000 - 24,000 - Certificates of deposit included in short-term investments 36,500 - 36,500 - Commercial paper 21,318 - 21,318 - Total assets at fair value $ 86,967 $ 5,149 $ 81,818 $ - December 31, 2015 Assets: Money market funds $ 12,353 $ 12,353 $ - $ - Certificates of deposit included in cash and cash equivalents 50,000 - 50,000 - Certificates of deposit included in short-term investments 20,000 - 20,000 - Commercial paper 24,952 - 24,952 - Total assets at fair value $ 107,305 $ 12,353 $ 94,952 $ -

Stock Incentive Plans (Tables)

Stock Incentive Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock Option Activity	The following table summarizes stock option activity during the six months ended June 30, 2016: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life in Years Total Aggregate Intrinsic Value (in thousands) Outstanding at December 31, 2015 1,437,583 $ 6.19 Options granted 699,275 10.04 Options exercised (21,802 ) 3.04 Outstanding at June 30, 2016 2,115,056 7.49 8.93 $ 6,811 Vested and expected to vest at June 30, 2016 2,115,056 7.49 8.93 $ 6,811 Exercisable at June 30, 2016 1,249,131 $ 5.92 8.55 $ 5,923
Summary of Stock-based Compensation Expense Recognized for Restricted Shares Stock Options and ESPP	Stock-based compensation expense recognized for restricted shares, stock options, and the ESPP has been reported in the statements of operations as follows (in thousands): Three months ended June 30, Six months ended June 30, 2016 2015 2016 2015 Research and development $ 525 $ 494 $ 881 $ 936 General and administrative 584 346 1,061 543 Total $ 1,109 $ 840 $ 1,942 $ 1,479
Summary of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance is as follows: June 30, 2016 December 31, 2015 Stock options issued and outstanding 2,115,056 1,437,583 Authorized for future stock awards or option grants 1,646,821 1,788,396 Authorized for future issuance under employee stock purchase plan 335,373 226,004 Total 4,097,250 3,451,983

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2016
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	Future minimum payments required under the lease as of June 30, 2016 for the years ended December 31 are as follows (in thousands): 2016 357 2017 725 2018 747 Total minimum lease payments $ 1,829

The Company and Basis of Pres19

The Company and Basis of Presentation - Additional Information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)Segment	Dec. 31, 2015USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accumulated deficit | $	$ (67,041)	$ (45,497)
Number of Operating Segments | Segment	1

Summary of Significant Accoun20

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Details) - shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share	2,208,858	1,784,421
Common Stock Options Issued and Outstanding
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share	2,115,056	1,479,578
Common Stock Subject to Repurchase
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded in the calculation of diluted net loss per share	93,802	304,843

Short-Term Investments - Summar

Short-Term Investments - Summary of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 57,822	$ 44,960
Unrealized Gains	2
Unrealized Losses	(6)	(8)
Fair Value	57,818	44,952
Certificates of Deposit
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	36,500	20,000
Fair Value	36,500	20,000
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	21,322	24,960
Unrealized Gains	2
Unrealized Losses	(6)	(8)
Fair Value	$ 21,318	$ 24,952

Short-Term Investments - Additi

Short-Term Investments - Additional Information (Details)	6 Months Ended
	Jun. 30, 2016
Investments Debt And Equity Securities [Abstract]
Maturity Period of Short Term Investments	All available-for-sale securities held at June 30, 2016 and December 31, 2015 had maturities of less than one year.

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - Fair Value, Measurements, Nonrecurring - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of assets	$ 0	$ 0
Fair value of liabilities	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - Fair Value Measurements Recurring Basis - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Assets:
Total assets at fair value	$ 86,967	$ 107,305
Money Market Funds
Assets:
Total assets at fair value	5,149	12,353
Certificates of Deposit Included in Cash and Cash Equivalents
Assets:
Total assets at fair value	24,000	50,000
Certificates of Deposit Included in Short-Term Marketable Securities
Assets:
Total assets at fair value	36,500	20,000
Commercial Paper
Assets:
Total assets at fair value	21,318	24,952
Level 1
Assets:
Total assets at fair value	5,149	12,353
Level 1 | Money Market Funds
Assets:
Total assets at fair value	5,149	12,353
Level 2
Assets:
Total assets at fair value	81,818	94,952
Level 2 | Certificates of Deposit Included in Cash and Cash Equivalents
Assets:
Total assets at fair value	24,000	50,000
Level 2 | Certificates of Deposit Included in Short-Term Marketable Securities
Assets:
Total assets at fair value	36,500	20,000
Level 2 | Commercial Paper
Assets:
Total assets at fair value	$ 21,318	$ 24,952

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Apr. 20, 2015	Feb. 10, 2015	Jun. 30, 2015	Jun. 30, 2016	Dec. 31, 2015
Class Of Stock [Line Items]
Common stock, shares issued				13,994,378	13,942,520
Common Stock
Class Of Stock [Line Items]
Convertible preferred stock in to shares of common stock	7,561,380
Initial Public Offering
Class Of Stock [Line Items]
Common stock, shares issued	4,800,000
Sale of common stock, price per share	$ 16
Net proceeds from sale of common stock	$ 69,300
Series B Convertible Preferred Stock
Class Of Stock [Line Items]
Proceeds from sales of Series B convertible preferred stock, gross issuance costs		$ 42,000	$ 41,921

Stock Incentive Plans - Additio

Stock Incentive Plans - Additional Information (Details) - USD ($)	6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cash received on stock options	$ 66,000	$ 116,000
Weighted average grant date fair values of stock options granted	$ 6.89
Grant date fair value of employee stock options, vested	$ 1,800,000
Unrecognized share-based compensation expense of unvested employee stock options	$ 8,000,000
Unvested stock options, Unrecognized cost expected to be recognized, Recognition Period	2 years 3 months 18 days
2015 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Price of stock option as percentage of estimated fair value of shares on date of grant	85.00%
Percentage of employee payroll deduction under the stock plan	15.00%
Unvested stock options, Unrecognized cost expected to be recognized, Recognition Period	1 year 10 months 24 days
Unrecognized share-based compensation expense of unvested employee stock options	$ 700,000
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cash received on stock options	$ 206,000		$ 341,000
Unvested shares subject to repurchase by the Company	93,802
Vesting terms	4 years

Stock Incentive Plans - Summary

Stock Incentive Plans - Summary of Stock Option Activity (Details) - Stock Options $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, beginning balance | shares	1,437,583
Number of stock options, granted | shares	699,275
Number of Shares, Options exercised | shares	(21,802)
Number of Shares, Outstanding ending balance | shares	2,115,056
Number of Shares, Vested and expected to vest | shares	2,115,056
Number of Shares, Exercisable | shares	1,249,131
Weighted Average Exercise Price, Outstanding, beginning balance | $ / shares	$ 6.19
Weighted Average Exercise Price, Options granted | $ / shares	10.04
Weighted Average Exercise Price, Options exercised | $ / shares	3.04
Weighted Average Exercise Price, Outstanding, ending balance | $ / shares	7.49
Weighted Average Exercise Price, Vested and expected to vest | $ / shares	7.49
Weighted Average Exercise Price, Exercisable | $ / shares	$ 5.92
Weighted Average Remaining Contractual Life in Years, Outstanding	8 years 11 months 5 days
Weighted Average Remaining Contractual Life in Years, Vested and expected to vest	8 years 11 months 5 days
Weighted Average Remaining Contractual Life in Years, Exercisable	8 years 6 months 18 days
Total Aggregate Intrinsic Value, Outstanding, ending balance | $	$ 6,811
Total Aggregate Intrinsic Value, Vested and expected to vest | $	6,811
Total Aggregate Intrinsic Value, Exercisable | $	$ 5,923

Stock Incentive Plans - Summa28

Stock Incentive Plans - Summary of Stock-Based Compensation Expense Recognized for Restricted Shares Stock Options and ESPP (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]
Stock-based compensation expense	$ 1,109	$ 840	$ 1,942	$ 1,479
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	525	494	881	936
General and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 584	$ 346	$ 1,061	$ 543

Stock Incentive Plans - Summa29

Stock Incentive Plans - Summary of Common Stock Reserved for Future Issuance (Details) - shares	Jun. 30, 2016	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	4,097,250	3,451,983
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options issued and outstanding	2,115,056	1,437,583
2015 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	1,646,821	1,788,396
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved for issuance	335,373	226,004

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	6 Months Ended
	Jun. 30, 2016USD ($)ClaimsOption	Jun. 30, 2015USD ($)
Commitments And Contingencies Disclosure [Abstract]
Number of claims and actions pending | Claims	0
Description of lease arrangements, operating leases	The lease expires in December 2018 with two individual two-year extensions.
Number of operating lease options for extension | Option	2
Operating lease expiration date	Dec. 31, 2018
Operating leases renewal term per options for extension	2 years
Lease rent expense | $	$ 360,000	$ 215,000
Contractual obligation, contract termination notice period	30 days

Commitments and Contingencies31

Commitments and Contingencies - Schedule of Future Minimum Lease Payment (Details) $ in Thousands	Jun. 30, 2016USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
2,016	$ 357
2,017	725
2,018	747
Total minimum lease payments	$ 1,829