Kura Oncology (KURA) 10-Q 7 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Aug. 02, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	KURA
Entity Registrant Name	Kura Oncology, Inc.
Entity Central Index Key	1,422,143
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		21,374,709

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	[1]
Current assets:
Cash and cash equivalents	$ 12,154	$ 9,725
Short-term investments	41,090	58,065
Accounts receivable, related party	304	295
Prepaid expenses and other current assets	1,187	725
Total current assets	54,735	68,810
Property and equipment, net	24	40
Other long-term assets	1,088	971
Total assets	55,847	69,821
Current liabilities:
Accounts payable and accrued expenses	4,179	4,681
Accounts payable and accrued expenses, related party	397	770
Current portion of long-term debt, net	500
Total current liabilities	5,076	5,451
Long-term debt, net	6,855	7,324
Other long-term liabilities	279	170
Total liabilities	12,210	12,945
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value; 200,000 shares authorized; 21,375 and 21,368 shares issued as of June 30, 2017 and December 31, 2016, respectively; and 19,988 and 19,348 shares outstanding as of June 30, 2017 and December 31, 2016, respectively, excluding 1,387 and 2,020 shares subject to repurchase as of June 30, 2017 and December 31, 2016, respectively	2	2
Additional paid-in capital	112,866	110,748
Accumulated other comprehensive loss	(22)	(18)
Accumulated deficit	(69,209)	(53,856)
Total stockholders' equity	43,637	56,876
Total liabilities and stockholders' equity	$ 55,847	$ 69,821
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Condensed Balance Sheets (Unau3

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016	[1]
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	21,375,000	21,368,000
Common stock, shares outstanding	19,988,000	19,348,000
Number of shares, subject to repurchase	1,387,000	2,020,000
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Expenses:
Research and development	$ 5,158	$ 3,959	$ 10,378	$ 7,526
Research and development, related party	494	977	787	2,059
General and administrative	2,217	1,838	4,292	4,203
General and administrative, related party	61	17	126	43
Total operating expenses	7,930	6,791	15,583	13,831
Other Income (Expense):
Management fee income, related party	195	195	390	495
Interest income	124	124	252	238
Interest expense	(209)	(189)	(412)	(189)
Total other income	110	130	230	544
Net loss	$ (7,820)	$ (6,661)	$ (15,353)	$ (13,287)
Net loss per share, basic and diluted	$ (0.40)	$ (0.36)	$ (0.78)	$ (0.72)
Weighted average number of shares used in computing net loss per share, basic and diluted	19,789	18,548	19,627	18,397
Comprehensive Loss:
Net loss	$ (7,820)	$ (6,661)	$ (15,353)	$ (13,287)
Other comprehensive income (loss):
Unrealized (loss) gain on marketable securities	(3)	34	(4)	132
Comprehensive loss	$ (7,823)	$ (6,627)	$ (15,357)	$ (13,155)

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016
Operating Activities
Net loss	$ (15,353)		$ (13,287)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	1,924		919
Non-cash interest expense	32		11
Depreciation expense	16		15
Amortization of discount on marketable securities	3		103
Changes in operating assets and liabilities:
Accounts receivable, related party	(9)		144
Prepaid expenses and other current assets	(462)		(352)
Other long-term assets	(117)		51
Accounts payable and accrued expenses	(502)		(882)
Accounts payable and accrued expenses, related party	(373)		117
Other long-term liabilities	109		22
Net cash used in operating activities	(14,732)		(13,139)
Investing Activities
Maturities of marketable securities	36,327		25,800
Purchases of marketable securities	(19,360)		(23,445)
Net cash provided by investing activities	16,967		2,355
Financing Activities
Proceeds from issuance of common stock, net	159
Proceeds from issuance of long-term debt, net			7,453
Proceeds from exercise of stock options	35
Net cash provided by financing activities	194		7,453
Net increase (decrease) in cash and cash equivalents	2,429		(3,331)
Cash and cash equivalents at beginning of period	9,725	[1]	15,443
Cash and cash equivalents at end of period	12,154
Supplemental disclosure of cash flow information:
Interest paid	$ 305		$ 57
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Organization and Basis of Prese

Organization and Basis of Presentation	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Organization and Basis of Presentation	1. Organization and Basis of Presentation The Company Kura Oncology, Inc. is a clinical-stage biopharmaceutical company committed to realizing the promise of precision medicines for the treatment of cancer. Our pipeline consists of small molecule product candidates that target cancer signaling pathways where there is a strong scientific and clinical rationale to improve outcomes by identifying those patients most likely to benefit from treatment. Kura Oncology, Inc. was a private Delaware corporation incorporated in the State of Delaware in August 2014. Effective March 6, 2015, Kura completed a reverse merger with a wholly owned subsidiary of Zeta Acquisition Corp. III, or Zeta, with Kura surviving the merger. Zeta was formally a “shell company” under applicable rules of the Securities and Exchange Commission, or SEC. On March 31, 2015, Kura merged with and into Zeta, with Kura surviving the merger, and Zeta changed its name to “Kura Oncology, Inc.” Basis of Presentation The accompanying unaudited condensed financial statements should be read in conjunction with the audited financial statements and notes thereto in our Annual Report on Form 10-K for the fiscal year ended December 31, 2016, as filed with the SEC on March 14, 2017, from which we derived our balance sheet as of December 31, 2016. The accompanying condensed financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP, for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, since they are interim statements, the accompanying condensed financial statements do not include all of the information and notes required by GAAP for complete financial statements. The accompanying condensed financial statements reflect all adjustments, consisting of normal recurring adjustments, that are, in the opinion of our management, necessary to a fair statement of the results for the interim periods presented. Interim results are not necessarily indicative of results for a full year. The preparation of the condensed financial statements in accordance with GAAP requires our management to make estimates and assumptions that affect the amounts reported on our condensed financial statements and accompanying notes. The amounts reported could differ under different estimates and assumptions. On an ongoing basis, we evaluate our estimates and judgments, which are based on historical and anticipated results and trends and on various other assumptions that management believes to be reasonable under the circumstances. By their nature, estimates are subject to an inherent degree of uncertainty and, as such, actual results may differ from management’s estimates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Comprehensive Loss Comprehensive loss is defined as the change in equity during the period from transactions and other events and non-owner sources. For the periods presented, accumulated other comprehensive loss consists solely of unrealized gains and losses on marketable securities. Net Loss per Share Net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of unvested restricted stock awards, outstanding stock options and outstanding warrants. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the antidilutive effect of the securities. Because of our net loss, unvested restricted stock awards, outstanding stock options and outstanding warrants are excluded from the calculation of diluted net loss per common share for the three and six months ended June 30, 2017 and 2016, due to the anti-dilutive effect of the securities. The following table summarizes the number of potentially dilutive securities that were excluded from our calculation of diluted net loss per share for the three and six months ended June 30, 2017 and 2016: Three and Six Months Ended June 30, 2017 2016 Unvested restricted stock awards 1,386,723 2,624,641 Stock options 2,214,547 1,178,449 Warrants 33,988 67,976 Total 3,635,258 3,871,066 Recent Accounting Pronouncements In May 2017, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2017-09, Compensation – Stock Compensation (Topic 718) – Scope of Modification Accounting that clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under this guidance, modification accounting is required only if the value, vesting conditions or classification of the award (as equity or liability) changes as a result of the change in terms or conditions. This guidance is effective for fiscal periods, and interim periods within those fiscal periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), that supersedes most current revenue recognition guidance, including industry-specific guidance. The guidance provides that an entity 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. This guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. This new standard is effective on January 1, 2018 for us. Early adoption is permitted. We plan to implement this standard on January 1, 2018. We currently plan to adopt using the modified retrospective transition approach; however, a final decision regarding the adoption method has not been made. The modified retrospective transition approach will recognize any changes from the beginning of the year of initial application through retained earnings with no restatement of comparative periods. We currently do not have any revenue contracts with customers and will review any new contracts entered into prior to the adoption of the new standard. The adoption of this guidance is not expected to have an impact on our condensed financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize a right-to-use asset and a lease obligation for all leases. Lessees are permitted to make an accounting policy election to not recognize an asset and liability for leases with a term of 12 months or less. Lessor accounting under the new standard is substantially unchanged. Additional qualitative and quantitative disclosures, including significant judgments made by management, will be required.

Investments

Investments	6 Months Ended
	Jun. 30, 2017
Investments All Other Investments [Abstract]
Investments	3. Investments We invest in available-for-sale securities consisting of money market funds, U.S. Treasury securities, corporate debt securities, commercial paper and government sponsored enterprise securities. Available-for-sale securities are classified as part of either cash and cash equivalents or short-term investments on our condensed balance sheets. The following tables summarize, by major security type, our investments that are measured at fair value on a recurring basis as of June 30, 2017 and December 31, 2016, respectively, in thousands: As of June 30, 2017 Maturity (years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds 1 or less $ 6,330 $ — $ — $ 6,330 Government agency securities 1 or less 2,994 — — 2,994 Commercial paper 1 or less 1,699 — — 1,699 Total cash equivalents 11,023 — — 11,023 Short-term investments: U.S. Treasury securities 1 or less 16,996 — (14 ) 16,982 Commercial paper 1 or less 15,664 — — 15,664 Corporate debt securities 1 or less 6,457 — (8 ) 6,449 Government agency securities 1 or less 1,995 — — 1,995 Total short-term investments 41,112 — (22 ) 41,090 Total $ 52,135 $ — $ (22 ) $ 52,113 As of December 31, 2016 Maturity (years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds 1 or less $ 5,762 $ — $ — $ 5,762 Commercial paper 1 or less 2,000 — — 2,000 Total cash equivalents 7,762 — — 7,762 Short-term investments: U.S. Treasury securities 2 or less 28,006 5 (9 ) 28,002 Commercial paper 1 or less 14,273 — — 14,273 Corporate debt securities 2 or less 13,603 — (14 ) 13,589 Government sponsored enterprise securities 1 or less 2,201 — — 2,201 Total short-term investments 58,083 5 (23 ) 58,065 Total $ 65,845 $ 5 $ (23 ) $ 65,827 The available-for-sale investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund our operations, as necessary. As of June 30, 2017, all of our short-term investments had maturities less than one year. There were no realized gains or losses for the six months ended June 30, 2017. As of June 30, 2017, $23.4 million of our marketable securities were in gross unrealized loss positions, all of which had been in such position for less than 12 months. We reviewed our marketable securities as of June 30, 2017 and determined that the unrealized losses were not considered to be other-than-temporary based upon (i) the financial strength of the issuing institution and (ii) the fact that all securities have been in an unrealized loss position for less than 12 months. In addition, we do not intend to sell these securities and it is not more likely than not that we will be required to sell these securities before the recovery of their amortized cost basis. As of June 30, 2017, we had not recognized any such impairment in our condensed financial statements.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements As a basis for considering assumptions that market participants would use in pricing an asset or liability, the guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: • Level 1 - Quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2 - Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable; and • Level 3 - Unobservable inputs in which little or no market activity exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing. Available-for-sale marketable securities consist of U.S. Treasury securities, which were measured at fair value using Level 1 inputs, and corporate debt securities, commercial paper and government sponsored enterprise securities, which were measured at fair value using Level 2 inputs. We determine the fair value of Level 2 related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. We validate the fair values of Level 2 financial instruments by comparing these fair values to a third-party pricing source. No transfers between levels have occurred during the periods presented. The following tables summarize, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy, in thousands: As of June 30, 2017 Total Estimated Fair Value Level 1 Level 2 Cash equivalents: Money market funds $ 6,330 $ 6,330 $ — Government agency securities 2,994 — 2,994 Commercial paper 1,699 — 1,699 Total cash equivalents 11,023 6,330 4,693 Short-term investments: U.S. Treasury securities 16,982 16,982 — Commercial paper 15,664 — 15,664 Corporate debt securities 6,449 — 6,449 Government agency securities 1,995 — 1,995 Total short-term investments 41,090 16,982 24,108 Total $ 52,113 $ 23,312 $ 28,801 As of December 31, 2016 Total Estimated Fair Value Level 1 Level 2 Cash equivalents: Money market funds $ 5,762 $ 5,762 $ — Commercial paper 2,000 — 2,000 Total cash equivalents 7,762 5,762 2,000 Short-term investments: U.S. Treasury securities 28,002 28,002 — Commercial paper 14,273 — 14,273 Corporate debt securities 13,589 — 13,589 Government sponsored enterprise securities 2,201 — 2,201 Total short-term investments 58,065 28,002 30,063 Total $ 65,827 $ 33,764 $ 32,063 We believe that our term loan facility bears interest at a rate that approximates prevailing market rates for instruments with similar characteristics and, accordingly, the carrying value of the term loan facility approximates fair value. The fair value of our term loan facility is determined using Level 2 inputs in the fair value hierarchy. See Note 6, Long-Term Debt, for further discussion of our term loan facility.

Accounts Payable and Accrued Li

Accounts Payable and Accrued Liabilities	6 Months Ended
	Jun. 30, 2017
Payables And Accruals [Abstract]
Accounts Payable and Accrued Liabilities	5. Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities consisted of the following, in thousands: June 30, 2017 December 31, 2016 Accounts payable $ 618 $ 638 Accrued compensation and benefits 1,161 1,907 Other accrued expenses 2,400 2,136 Total accounts payable and accrued expenses $ 4,179 $ 4,681

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Long-Term Debt	6. Long-Term Debt On April 27, 2016, we entered into a loan and security agreement, or the Loan Agreement, with Oxford Finance LLC and Silicon Valley Bank, or the Lenders, pursuant to which the Lenders provided a loan facility of up to $20.0 million. Upon entering into the Loan Agreement, we borrowed $7.5 million from the Lenders, or Term A Loan. We may, at our sole discretion, borrow up to an additional $12.5 million at a certain specified time, or Term B Loan, and together with the Term A Loan, the Term Loans. In May 2017, the Loan Agreement was amended to extend the draw period on the Term B Loan and modify the terms of the unused fee, or Loan Amendment. The Term B Loan originally could be drawn between December 31, 2016 and May 1, 2017, subject to our successful advancement of KO-947, a small molecule inhibitor of extracellular signal regulated kinase, into Phase 1 clinical trials. Under the Loan Amendment, the Term B Loan may be drawn between August 1, 2017 and October 31, 2017. In addition, each Term B Loan must be in an amount equal to the lesser of $5.0 million or the amount that is remaining under the Term B Loan. All of the Term Loans will mature on November 1, 2020 , or Maturity Date. Repayment of the We are subject to customary affirmative and restrictive covenants under the term loan facility. Our obligations under the Loan Agreement are secured by a first priority security interest in substantially all of our current and future assets, other than our intellectual property. We have also agreed not to encumber our intellectual property assets, except as permitted by the Loan Agreement. The Loan Agreement also contains customary indemnification obligations and customary events of default, including, among other things, our failure to fulfill certain obligations under the Loan Agreement and the occurrence of a material adverse change in our business, operations, or condition (financial or otherwise), a material impairment of the prospect of repayment of any portion of the loan, or a material impairment in the perfection or priority of Lenders’ lien in the collateral or in the value of such collateral. In the event of default by us under the Loan Agreement, the Lenders would be entitled to exercise their remedies thereunder, including the right to accelerate the debt, upon which we may be required to repay all amounts then outstanding under the Loan Agreement. The conditional exercisable call option related to the event of default is considered to be an embedded derivative which is required to be bifurcated and accounted for as a separate financial instrument. In the periods presented, the value of the embedded derivative is not material, but could become material in future periods if an event of default became more probable than is currently estimated. As of June 30, 2017, we were in compliance with all material covenants under the Loan Agreement and there had been no material adverse change. In connection with the Term A Loan, we issued to the Lenders warrants to purchase up to 67,976 shares of our common stock at an exercise price of $3.31 per share, or the Warrants. The Warrants are exercisable, in whole or in part, and will terminate on the earlier of April 27, 2026 or the closing of certain merger or consolidation transactions In February 2017, Silicon Valley Bank exercised its warrant to purchase 33,988 shares of common stock in a cashless exercise resulting in the issuance of 17,070 shares of our common stock. The warrant issued to Oxford Finance LLC to purchase up to 33,988 shares of our common stock remains outstanding as of June 30, 2017. If we borrow under the Term B Loan, upon the funding of the Term B Loan, we will issue to the Lenders additional warrants to purchase shares of our common stock equal to 3.00% of each Term B Loan amount divided by the lower of (i) the ten day average closing price of our common stock reported on the Nasdaq Global Select Market prior to funding or (ii) the closing price of our common stock reported on the Nasdaq Global Select Market on the day prior to funding. Such lower amount of (i) and (ii) above will also be the exercise price per share for such warrants. The terms of such warrants would be substantially the same as those contained in the Warrants. The following table summarizes future minimum payments under the term loan facility as of June 30, 2017, in thousands: Year Ending December 31, 2017 $ 315 2018 2,340 2019 3,366 2020 3,428 Total future minimum payments 9,449 Less: interest payments (1,949 ) Principal amount of long-term debt 7,500 Less: Unamortized discount (145 ) Long-term debt, net of unamortized discount 7,355 Current portion of long-term debt (500 ) Long-term debt, net $ 6,855

Equity Incentive Plan

Equity Incentive Plan	6 Months Ended
	Jun. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity Incentive Plan	7. Equity Incentive Plan The following table summarizes share-based compensation expense for all equity awards granted, in thousands: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Research and development $ 678 $ 231 $ 1,266 $ 547 General and administrative 352 198 658 372 Total share-based compensation expense $ 1,030 $ 429 $ 1,924 $ 919 For the three months ended June 30, 2017 and 2016, we recognized share-based compensation expense related to stock options of $552,000 and $251,000, respectively, of which $22,000 and $5,000 related to non-employee stock options, respectively. For the six months ended June 30, 2017 and 2016, we recognized share-based compensation expense related to stock options of $1.0 million and $501,000, respectively, of which $41,000 and $13,000 related to non-employee stock options, respectively. For the three months ended June 30, 2017 and 2016, we recognized share-based compensation expense related to restricted stock awards totaling $478,000 and $179,000, respectively, of which $445,000 and $146,000 related to non-employee restricted stock awards, respectively. For the six months ended June 30, 2017 and 2016, we recognized share-based compensation expense related to restricted stock awards totaling $894,000 and $418,000, respectively, of which $828,000 and $352,000 related to non-employee restricted stock awards, respectively. As of June 30, 2017, unrecognized compensation costs related to employee stock options and restricted stock awards were approximately $6.2 million and $162,000, respectively, which are expected to be recognized over a weighted average period of approximately 2.9 years and 1.2 years, respectively.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	8. Related Party Transactions Our president and chief executive officer is also the sole managing member of Araxes Pharma LLC, or • Asset Purchase Agreement Under our asset purchase agreement with Araxes, in the three and six months ended June 30, 2017, we paid a milestone payment of $200,000 to Araxes following dosing of the first patient in the first KO-947 Phase 1 clinical trial in April 2017. • Facility Sublease We sublease office space from Wellspring Biosciences, Inc., or Wellspring, a wholly owned subsidiary of Araxes. In December 2016, we entered into a third amendment to the sublease agreement with Wellspring for office space in La Jolla, California, or Sublease, pursuant to which the Sublease expired in June 2017. In December 2016, we also entered into a new sublease agreement with Wellspring for office space in San Diego, California, or New Sublease. The New Sublease commenced in June 2017 and will expire on October 31, 2019. • Management Fees We have a management services agreement with Araxes pursuant to which Araxes pays us a fixed fee of $65,000 per month for management services. In addition, the agreement allows for Araxes to reimburse us an amount equal to the number of full time equivalents, or FTE, performing research and development services for Araxes, at an annual FTE rate of approximately $350,000, plus actual expenses as reasonably incurred. The initial term expired on December 31, 2015 but, pursuant to the terms of the agreement, renews automatically for additional consecutive one-year periods. The agreement may be terminated by either party with a notice of at least 30 days prior to the expiration of the then-renewal term. For the three months ended June 30, 2017 and 2016, we recorded reimbursements of $102,000 and $85,000, respectively, and for the six months ended June 30, 2017 and 2016, we recorded reimbursements of $248,000 and $191,000, respectively, for research and development services provided to Araxes, which was recorded as a reduction to research and development expenses on our condensed statements of operations and comprehensive loss. As of June 30, 2017 and December 31, 2016, $304,000 and $295,000 related to management fees and reimbursements of research and development services, respectively, are included in accounts receivable, related party on our condensed balance sheets. • Services Agreement We have a services agreement with Wellspring which allows for payment of research and development services provided to us of an amount equal to the number of FTE’s performing the services, at an annual FTE rate of $400,000, plus actual expenses as reasonably incurred. The initial term of this services agreement expired on December 31, 2015 but, pursuant to the terms of the agreement, renews automatically for additional consecutive one-year periods. The agreement may be terminated by either party with a notice of at least 30 days prior to the expiration of the then-renewal term. For the three months ended June 30, 2017 and 2016, we recognized $347,000 and $1.0 million, respectively, and for the six months ended June 30, 2017 and 2016, we recognized $739,000 and $2.2 million, respectively, from research and development services provided to us under this agreement as research and development expense, related party on our condensed statements of operations and comprehensive loss. As of June 30, 2017 and December 31, 2016, $361,000 and $770,000, respectively, related to research and development services under this agreement are included in accounts payable and accrued expenses, related party on our condensed balance sheets.

Summary of Significant Accoun14

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as the change in equity during the period from transactions and other events and non-owner sources. For the periods presented, accumulated other comprehensive loss consists solely of unrealized gains and losses on marketable securities.
Net Loss per Share	Net Loss per Share Net loss per common share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of unvested restricted stock awards, outstanding stock options and outstanding warrants. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding due to the antidilutive effect of the securities. Because of our net loss, unvested restricted stock awards, outstanding stock options and outstanding warrants are excluded from the calculation of diluted net loss per common share for the three and six months ended June 30, 2017 and 2016, due to the anti-dilutive effect of the securities. The following table summarizes the number of potentially dilutive securities that were excluded from our calculation of diluted net loss per share for the three and six months ended June 30, 2017 and 2016: Three and Six Months Ended June 30, 2017 2016 Unvested restricted stock awards 1,386,723 2,624,641 Stock options 2,214,547 1,178,449 Warrants 33,988 67,976 Total 3,635,258 3,871,066
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2017, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2017-09, Compensation – Stock Compensation (Topic 718) – Scope of Modification Accounting that clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under this guidance, modification accounting is required only if the value, vesting conditions or classification of the award (as equity or liability) changes as a result of the change in terms or conditions. This guidance is effective for fiscal periods, and interim periods within those fiscal periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606), that supersedes most current revenue recognition guidance, including industry-specific guidance. The guidance provides that an entity 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. This guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, and assets recognized from costs incurred to obtain or fulfill a contract. This new standard is effective on January 1, 2018 for us. Early adoption is permitted. We plan to implement this standard on January 1, 2018. We currently plan to adopt using the modified retrospective transition approach; however, a final decision regarding the adoption method has not been made. The modified retrospective transition approach will recognize any changes from the beginning of the year of initial application through retained earnings with no restatement of comparative periods. We currently do not have any revenue contracts with customers and will review any new contracts entered into prior to the adoption of the new standard. The adoption of this guidance is not expected to have an impact on our condensed financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842), which requires lessees to recognize a right-to-use asset and a lease obligation for all leases. Lessees are permitted to make an accounting policy election to not recognize an asset and liability for leases with a term of 12 months or less. Lessor accounting under the new standard is substantially unchanged. Additional qualitative and quantitative disclosures, including significant judgments made by management, will be required.

Summary of Significant Accoun15

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Summary of Number of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share	The following table summarizes the number of potentially dilutive securities that were excluded from our calculation of diluted net loss per share for the three and six months ended June 30, 2017 and 2016: Three and Six Months Ended June 30, 2017 2016 Unvested restricted stock awards 1,386,723 2,624,641 Stock options 2,214,547 1,178,449 Warrants 33,988 67,976 Total 3,635,258 3,871,066

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2017
Investments All Other Investments [Abstract]
Investments Measured at Fair Value on Recurring Basis	The following tables summarize, by major security type, our investments that are measured at fair value on a recurring basis as of June 30, 2017 and December 31, 2016, respectively, in thousands: As of June 30, 2017 Maturity (years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds 1 or less $ 6,330 $ — $ — $ 6,330 Government agency securities 1 or less 2,994 — — 2,994 Commercial paper 1 or less 1,699 — — 1,699 Total cash equivalents 11,023 — — 11,023 Short-term investments: U.S. Treasury securities 1 or less 16,996 — (14 ) 16,982 Commercial paper 1 or less 15,664 — — 15,664 Corporate debt securities 1 or less 6,457 — (8 ) 6,449 Government agency securities 1 or less 1,995 — — 1,995 Total short-term investments 41,112 — (22 ) 41,090 Total $ 52,135 $ — $ (22 ) $ 52,113 As of December 31, 2016 Maturity (years) Amortized Cost Unrealized Gains Unrealized Losses Fair Value Cash equivalents: Money market funds 1 or less $ 5,762 $ — $ — $ 5,762 Commercial paper 1 or less 2,000 — — 2,000 Total cash equivalents 7,762 — — 7,762 Short-term investments: U.S. Treasury securities 2 or less 28,006 5 (9 ) 28,002 Commercial paper 1 or less 14,273 — — 14,273 Corporate debt securities 2 or less 13,603 — (14 ) 13,589 Government sponsored enterprise securities 1 or less 2,201 — — 2,201 Total short-term investments 58,083 5 (23 ) 58,065 Total $ 65,845 $ 5 $ (23 ) $ 65,827

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Schedule Of Fair Value Measurements, By Major Security Type	The following tables summarize, by major security type, our cash equivalents and short-term investments that are measured at fair value on a recurring basis and are categorized using the fair value hierarchy, in thousands: As of June 30, 2017 Total Estimated Fair Value Level 1 Level 2 Cash equivalents: Money market funds $ 6,330 $ 6,330 $ — Government agency securities 2,994 — 2,994 Commercial paper 1,699 — 1,699 Total cash equivalents 11,023 6,330 4,693 Short-term investments: U.S. Treasury securities 16,982 16,982 — Commercial paper 15,664 — 15,664 Corporate debt securities 6,449 — 6,449 Government agency securities 1,995 — 1,995 Total short-term investments 41,090 16,982 24,108 Total $ 52,113 $ 23,312 $ 28,801 As of December 31, 2016 Total Estimated Fair Value Level 1 Level 2 Cash equivalents: Money market funds $ 5,762 $ 5,762 $ — Commercial paper 2,000 — 2,000 Total cash equivalents 7,762 5,762 2,000 Short-term investments: U.S. Treasury securities 28,002 28,002 — Commercial paper 14,273 — 14,273 Corporate debt securities 13,589 — 13,589 Government sponsored enterprise securities 2,201 — 2,201 Total short-term investments 58,065 28,002 30,063 Total $ 65,827 $ 33,764 $ 32,063

Accounts Payable and Accrued 18

Accounts Payable and Accrued Liabilities (Tables)	6 Months Ended
	Jun. 30, 2017
Payables And Accruals [Abstract]
Accounts Payable and Accrued Liabilities	Accounts payable and accrued liabilities consisted of the following, in thousands: June 30, 2017 December 31, 2016 Accounts payable $ 618 $ 638 Accrued compensation and benefits 1,161 1,907 Other accrued expenses 2,400 2,136 Total accounts payable and accrued expenses $ 4,179 $ 4,681

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Future Minimum Payments under Term Loan Facility	The following table summarizes future minimum payments under the term loan facility as of June 30, 2017, in thousands: Year Ending December 31, 2017 $ 315 2018 2,340 2019 3,366 2020 3,428 Total future minimum payments 9,449 Less: interest payments (1,949 ) Principal amount of long-term debt 7,500 Less: Unamortized discount (145 ) Long-term debt, net of unamortized discount 7,355 Current portion of long-term debt (500 ) Long-term debt, net $ 6,855

Equity Incentive Plan (Tables)

Equity Incentive Plan (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Share-based Compensation Expense	The following table summarizes share-based compensation expense for all equity awards granted, in thousands: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 Research and development $ 678 $ 231 $ 1,266 $ 547 General and administrative 352 198 658 372 Total share-based compensation expense $ 1,030 $ 429 $ 1,924 $ 919

Summary of Significant Accoun21

Summary of Significant Accounting Policies - Summary of Number of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	3,635,258	3,871,066	3,635,258	3,871,066
Unvested Restricted Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	1,386,723	2,624,641	1,386,723	2,624,641
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	2,214,547	1,178,449	2,214,547	1,178,449
Warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	33,988	67,976	33,988	67,976

Investments - Investments Measu

Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Schedule Of Available For Sale Securities [Line Items]
Short-term investments	$ 41,090	$ 58,065	[1]
Fair Value Measurements on Recurring Basis
Schedule Of Available For Sale Securities [Line Items]
Cash equivalents, Amortized Cost	11,023	7,762
Cash equivalents, Fair Value	11,023	7,762
Short-term investments, Amortized Cost	41,112	58,083
Short-term investments, Unrealized Gains		5
Short-term investments, Unrealized Losses	(22)	(23)
Short-term investments	41,090	58,065
Cash equivalents and Short-term investments, Amortized Cost	52,135	65,845
Cash equivalents and Short-term investments, Fair Value	$ 52,113	$ 65,827
Fair Value Measurements on Recurring Basis | Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	1 or less
Cash equivalents, Amortized Cost	$ 6,330	$ 5,762
Cash equivalents, Fair Value	$ 6,330	$ 5,762
Fair Value Measurements on Recurring Basis | Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less
Cash equivalents, Amortized Cost	$ 2,994
Cash equivalents, Fair Value	2,994
Short-term investments, Amortized Cost	1,995
Short-term investments	$ 1,995
Fair Value Measurements on Recurring Basis | Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	1 or less
Cash equivalents, Amortized Cost	$ 1,699	$ 2,000
Cash equivalents, Fair Value	1,699	2,000
Short-term investments, Amortized Cost	15,664	14,273
Short-term investments	$ 15,664	$ 14,273
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	2 or less
Short-term investments, Amortized Cost	$ 16,996	$ 28,006
Short-term investments, Unrealized Gains		5
Short-term investments, Unrealized Losses	(14)	(9)
Short-term investments	$ 16,982	$ 28,002
Fair Value Measurements on Recurring Basis | Corporate Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)	1 or less	2 or less
Short-term investments, Amortized Cost	$ 6,457	$ 13,603
Short-term investments, Unrealized Losses	(8)	(14)
Short-term investments	$ 6,449	$ 13,589
Fair Value Measurements on Recurring Basis | Government Sponsored Enterprise Securities
Schedule Of Available For Sale Securities [Line Items]
Maturities (years)		1 or less
Short-term investments, Amortized Cost		$ 2,201
Short-term investments		$ 2,201
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Investments - Additional Inform

Investments - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2017USD ($)
Investments All Other Investments [Abstract]
Available-for-sale securities, realized gains or losses	$ 0
Marketable securities gross unrealized loss positions for less than twelve months	$ 23,400,000
Short-term investments maturities, description	As of June 30, 2017, all of our short-term investments had maturities less than one year.

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values of Investment Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 41,090	$ 58,065	[1]
Fair Value Measurements on Recurring Basis
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	11,023	7,762
Short-term investments	41,090	58,065
Cash equivalents and short-term investments	52,113	65,827
Fair Value Measurements on Recurring Basis | Government Sponsored Enterprise Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		2,201
Fair Value Measurements on Recurring Basis | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	6,330	5,762
Fair Value Measurements on Recurring Basis | Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	2,994
Short-term investments	1,995
Fair Value Measurements on Recurring Basis | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	1,699	2,000
Short-term investments	15,664	14,273
Fair Value Measurements on Recurring Basis | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	16,982	28,002
Fair Value Measurements on Recurring Basis | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	6,449	13,589
Fair Value Measurements on Recurring Basis | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	6,330	5,762
Short-term investments	16,982	28,002
Cash equivalents and short-term investments	23,312	33,764
Fair Value Measurements on Recurring Basis | Level 1 | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	6,330	5,762
Fair Value Measurements on Recurring Basis | Level 1 | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	16,982	28,002
Fair Value Measurements on Recurring Basis | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	4,693	2,000
Short-term investments	24,108	30,063
Cash equivalents and short-term investments	28,801	32,063
Fair Value Measurements on Recurring Basis | Level 2 | Government Sponsored Enterprise Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments		2,201
Fair Value Measurements on Recurring Basis | Level 2 | Government Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	2,994
Short-term investments	1,995
Fair Value Measurements on Recurring Basis | Level 2 | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	1,699	2,000
Short-term investments	15,664	14,273
Fair Value Measurements on Recurring Basis | Level 2 | Corporate Debt Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short-term investments	$ 6,449	$ 13,589
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Accounts Payable and Accrued 25

Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Payables And Accruals [Abstract]
Accounts payable	$ 618	$ 638
Accrued compensation and benefits	1,161	1,907
Other accrued expenses	2,400	2,136
Total accounts payable and accrued expenses	$ 4,179	$ 4,681	[1]
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail) - USD ($)	May 12, 2017	Apr. 27, 2016	Feb. 28, 2017	Jun. 30, 2017
Debt Instrument [Line Items]
Maximum borrowing capacity under term loans		$ 20,000,000
Principal amount outstanding on loan				$ 7,500,000
Term loan remaining borrowing capacity		12,500,000
Additional borrowing description				We may, at our sole discretion, borrow up to an additional $12.5 million at a certain specified time, or Term B Loan, and together with the Term A Loan, the Term Loans. In May 2017, the Loan Agreement was amended to extend the draw period on the Term B Loan and modify the terms of the unused fee, or Loan Amendment. The Term B Loan originally could be drawn between December 31, 2016 and May 1, 2017, subject to our successful advancement of KO-947, a small molecule inhibitor of extracellular signal regulated kinase, into Phase 1 clinical trials. Under the Loan Amendment, the Term B Loan may be drawn between August 1, 2017 and October 31, 2017.
Silicon Valley Bank
Debt Instrument [Line Items]
Warrants issued to purchase of common stock			33,988
Common stock, shares issued			17,070
Maximum | Oxford Finance LLC
Debt Instrument [Line Items]
Warrants issued to purchase of common stock				33,988
Term A Loan
Debt Instrument [Line Items]
Principal amount outstanding on loan		7,500,000
Final payment due on the maturity date		563,000
Fair Value Of Warrants		$ 172,000
Term A Loan | Term Loan Warrants
Debt Instrument [Line Items]
Warrants exercisable exercise price		$ 3.31
Warrants termination date				Apr. 27, 2026
Volatility Rate		70.92%
Expected Term		10 years
Risk Free Interest Rate		2.11%
Dividend yield		0.00%
Term A Loan | Maximum | Term Loan Warrants
Debt Instrument [Line Items]
Warrants issued to purchase of common stock		67,976
Term B Loan
Debt Instrument [Line Items]
Description of required debt amount				each Term B Loan must be in an amount equal to the lesser of $5.0 million or the amount that is remaining under the Term B Loan.
Term B Loan | Term Loan Warrants
Debt Instrument [Line Items]
Warrant shares percentage issued of loan amount		3.00%
Number of trading days for average closing price		10 days
Term B Loan | Minimum
Debt Instrument [Line Items]
Term B Loan Minimum draw amount		$ 5,000,000
Term Loans
Debt Instrument [Line Items]
Term loan facility maturity date		Nov. 1, 2020
Description of term loan payment terms				All of the Term Loans will mature on November 1, 2020, or Maturity Date. Repayment of the Term Loans is interest only through May 1, 2018, followed by 30 equal monthly payments of principal plus accrued interest commencing on June 1, 2018
Percentage of prime rate included in effective interest rate		4.25%
Final payment as a percentage of amounts borrowed		7.50%
Team loan effective interest rate description				The per annum interest rate for any outstanding Term Loans is the greater of (i) 7.75% and (ii) the sum of (a) the prime rate reported in The Wall Street Journal on the last business day of the month that immediately precedes the month in which the interest will accrue, plus (b) 4.25%.
Minimum percentage of interest rate on outstanding borrowings				8.25%
Unused fee description				unused fee on the earlier of November 1, 2017, extended from May 2, 2017 under the Loan Amendment, or prior repayment of the Term Loans in an amount equal to (a) 2.75%, amended from 2.00%, multiplied by (b) $20.0 million minus the aggregate amount of the Term Loans drawn on or before October 31, 2017, extended from May 1, 2017.
Term Loans | Base Rate
Debt Instrument [Line Items]
Commitment fee percentage on unused capacity		2.00%
Term Loans | Base Rate | Loan Amendment
Debt Instrument [Line Items]
Commitment fee percentage on unused capacity	2.75%
Term Loans | Transaction Occurring Assumption One
Debt Instrument [Line Items]
Prepayment fee equal to outstanding principal amount		1.00%
Term Loans | Transaction Occurring Assumption Two
Debt Instrument [Line Items]
Prepayment fee equal to outstanding principal amount		2.00%
Term Loans | Transaction Occurring Assumption Three
Debt Instrument [Line Items]
Prepayment fee equal to outstanding principal amount		3.00%
Term Loans | Minimum | Base Rate
Debt Instrument [Line Items]
Minimum percentage of interest rate on outstanding borrowings		7.75%

Long-Term Debt - Future Minimum

Long-Term Debt - Future Minimum Payments under Term Loan Facility (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	[1]
Debt Disclosure [Abstract]
2,017	$ 315
2,018	2,340
2,019	3,366
2,020	3,428
Total future minimum payments	9,449
Less: interest payments	(1,949)
Principal amount of long-term debt	7,500
Less: Unamortized discount	(145)
Long-term debt, net of unamortized discount	7,355
Current portion of long-term debt	(500)
Long-term debt, net	$ 6,855	$ 7,324
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.

Equity Incentive Plan - Summary

Equity Incentive Plan - Summary of Share-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 1,030	$ 429	$ 1,924	$ 919
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	678	231	1,266	547
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 352	$ 198	$ 658	$ 372

Equity Incentive Plan - Additio

Equity Incentive Plan - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 1,030,000	$ 429,000	$ 1,924,000	$ 919,000
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	552,000	251,000	1,000,000	501,000
Non-employee share based compensation expense	22,000	5,000	41,000	13,000
Unrecognized stock option compensation expenses	6,200,000		$ 6,200,000
Weighted average service period			2 years 10 months 24 days
Restricted Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	478,000	179,000	$ 894,000	418,000
Non-employee share based compensation expense	445,000	$ 146,000	828,000	$ 352,000
Unrecognized stock option compensation expenses	$ 162,000,000		$ 162,000,000
Weighted average service period			1 year 2 months 12 days

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	Apr. 30, 2016	Oct. 01, 2014	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Accounts receivable, related party			$ 304,000		$ 304,000		$ 295,000	[1]
Research and development, related party			494,000	$ 977,000	787,000	$ 2,059,000
Accounts payable and accrued expenses, related party			397,000		$ 397,000		770,000	[1]
Araxes Pharma LLC
Related Party Transaction [Line Items]
Management Fee, Description					We have a management services agreement with Araxes pursuant to which Araxes pays us a fixed fee of $65,000 per month for management services.
Research and development sevices reimbursement, description					In addition, the agreement allows for Araxes to reimburse us an amount equal to the number of full time equivalents, or FTE, performing research and development services for Araxes, at an annual FTE rate of approximately $350,000, plus actual expenses as reasonably incurred. The initial term expired on December 31, 2015 but, pursuant to the terms of the agreement, renews automatically for additional consecutive one-year periods. The agreement may be terminated by either party with a notice of at least 30 days prior to the expiration of the then-renewal term.
Management service agreement, fixed	$ 65,000
Service Agreement for research and development	$ 350,000
Agreement expiration date		Dec. 31, 2015
Agreement termination notice period		30 days
Amount received on research and development services			102,000	85,000	$ 248,000	191,000
Accounts receivable, related party			304,000		304,000		295,000
Araxes Pharma LLC | Araxes Asset Purchase Agreement
Related Party Transaction [Line Items]
Milestone payment paid			200,000		200,000
Wellspring Biosciences Inc
Related Party Transaction [Line Items]
Rent expense related to office space sublease			32,000	26,000	$ 63,000	53,000
Sublease agreement description					In December 2016, we entered into a third amendment to the sublease agreement with Wellspring for office space in La Jolla, California, or Sublease, pursuant to which the Sublease expired in June 2017. In December 2016, we also entered into a new sublease agreement with Wellspring for office space in San Diego, California, or New Sublease.
Research and development expense payment, description					We have a services agreement with Wellspring which allows for payment of research and development services provided to us of an amount equal to the number of FTE’s performing the services, at an annual FTE rate of $400,000, plus actual expenses as reasonably incurred. The initial term of this services agreement expired on December 31, 2015 but, pursuant to the terms of the agreement, renews automatically for additional consecutive one-year periods. The agreement may be terminated by either party with a notice of at least 30 days prior to the expiration of the then-renewal term.
Agreement expiration date		Dec. 31, 2015
Agreement termination notice period		30 days
Research and development services expense at full time equivalents rate		$ 400,000
Research and development, related party			347,000	$ 1,000,000	$ 739,000	$ 2,200,000
Accounts payable and accrued expenses, related party			$ 361,000		$ 361,000		$ 770,000
Wellspring Biosciences Inc | La Jolla California
Related Party Transaction [Line Items]
Sublease expiration date					Jun. 30, 2017
Wellspring Biosciences Inc | San Diego California
Related Party Transaction [Line Items]
Sublease expiration date					Oct. 31, 2019
Sublease commencement date					Jun. 30, 2017
[1]	The balance sheet data at December 31, 2016 has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by U.S. generally accepted accounting principles for complete financial statements.