View Filing Data

147,747

162,866

Prepaid expenses and other current assets

179

224

1,882

1,988

Total current assets

167,586

181,197

Other long-term assets

1,772

1,166

Other long-term assets, related party

259

Total assets

169,617

182,379

Current liabilities:

Accounts payable and accrued expenses

11,782

13,385

Accounts payable and accrued expenses, related party

361

230

Total current liabilities

12,143

13,615

Long-term debt, net

7,500

Other long-term liabilities

385

279

Other long-term liabilities, related party

Total liabilities

20,052

21,394

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; 38,169 and 38,148 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively

Additional paid-in capital

313,220

310,849

Accumulated other comprehensive income (loss)

(131)

Accumulated deficit

(163,677)

(149,737)

Total stockholders' equity

149,565

160,985

Total liabilities and stockholders' equity

$ 169,617

$ 182,379

[1]	The balance sheet data at December 31, 2018 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 (Unaudited) (Parenthetical) - $ / shares

Mar. 31, 2019

Dec. 31, 2018

^[1]

Statement Of Financial Position [Abstract]

Preferred stock, par value

$ 0.0001

Preferred stock, shares authorized

10,000,000

Preferred stock, shares issued

Preferred stock, shares outstanding

Common stock, par value

$ 0.0001

Common stock, shares authorized

200,000,000

Common stock, shares issued

38,169,000

38,148,000

Common stock, shares outstanding

38,169,000

38,148,000

[1]	The balance sheet data at December 31, 2018 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 Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating Expenses:
Research and development	$ 10,329	$ 11,267
Research and development, related party	53	299
General and administrative	4,482	3,366
General and administrative, related party	87	59
Total operating expenses	14,951	14,991
Other Income (Expense):
Management fee income, related party	126	195
Interest income	1,030	450
Interest expense	(145)	(258)
Total other income	1,011	387
Net Loss	$ (13,940)	$ (14,604)
Net loss per share, basic and diluted	$ (0.37)	$ (0.46)
Weighted average number of shares used in computing net loss per share, basic and diluted	38,168	31,829
Comprehensive Loss:
Net loss	$ (13,940)	$ (14,604)
Other comprehensive income (loss):
Unrealized gain (loss) on marketable securities	149	(19)
Comprehensive Loss	$ (13,791)	$ (14,623)

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($)
shares in Thousands, $ in Thousands

Total

Common Stock

Additional Paid- In Capital

Accumulated Other Comprehensive Income (Loss)

Accumulated Deficit

Beginning balance at Dec. 31, 2017

$ 79,865

$ 3

$ 169,201

$ (49)

$ (89,290)

Beginning balance (in shares) at Dec. 31, 2017

29,424

Issuance of common stock, net of offering costs

57,378

Issuance of common stock, net of offering costs, ( in shares)

3,137

Share-based compensation expense

2,179

Restricted stock awards vested

Restricted stock awards vested (in shares)

295

Other comprehensive income (loss)

(19)

Net loss

(14,604)

Ending balance at Mar. 31, 2018

124,800

$ 3

228,759

(68)

(103,894)

Ending balance (in shares) at Mar. 31, 2018

32,856

Beginning balance at Dec. 31, 2018

160,985

^[1]

$ 4

310,849

(131)

(149,737)

Beginning balance (in shares) at Dec. 31, 2018

38,148

Share-based compensation expense

2,269

Issuance of common stock from exercise of options

102

Issuance of common stock from exercise of options (in shares)

Other comprehensive income (loss)

149

Net loss

(13,940)

Ending balance at Mar. 31, 2019

$ 149,565

$ 4

$ 313,220

$ 18

$ (163,677)

Ending balance (in shares) at Mar. 31, 2019

38,169

[1]	The balance sheet data at December 31, 2018 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 Cash Flows (Unaudited) - USD ($)
$ in Thousands

3 Months Ended

Mar. 31, 2019

Mar. 31, 2018

Operating Activities

Net loss

$ (13,940)

$ (14,604)

Adjustments to reconcile net loss to net cash used in operating activities:

Share-based compensation expense

2,269

2,179

Non-cash interest expense

Depreciation expense

Amortization of premium and accretion of discount on marketable securities, net

(540)

(275)

Changes in operating assets and liabilities:

Prepaid expenses and other current assets

(41)

146

(624)

Other long-term assets

(239)

(163)

Other long-term assets, related party

Accounts payable and accrued expenses

(1,920)

440

Accounts payable and accrued expenses, related party

(145)

117

Other long-term liabilities

Net cash used in operating activities

(14,251)

(12,851)

Investing Activities

Maturities and sales of marketable securities

66,656

46,493

Purchases of marketable securities

(50,848)

(76,207)

Net cash provided by (used in) investing activities

15,808

(29,714)

Financing Activities

Proceeds from issuance of common stock, net

57,650

Proceeds from exercise of stock options

102

Net cash provided by financing activities

102

57,650

Net increase in cash and cash equivalents

1,659

15,085

Cash and cash equivalents at beginning of period

16,119

^[1]

11,433

Cash and cash equivalents at end of period

$ 17,778

$ 26,518

[1]	The balance sheet data at December 31, 2018 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 Presentation

3 Months Ended

Mar. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [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, and we intend to pair them with molecular or cellular diagnostics to identify those patients most likely to respond to treatment. We plan to advance our product candidates through a combination of internal development and strategic partnerships and maintain significant development and commercial rights.

References in these Notes to Unaudited Condensed Financial Statements to the “Company,” “we,” “our” or “us,” refer 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, 2018, as filed with the Securities and Exchange Commission on March 5, 2019, from which we derived our balance sheet as of December 31, 2018. The accompanying unaudited 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 unaudited condensed financial statements do not include all of the information and notes required by GAAP for complete financial statements. The accompanying unaudited 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 unaudited condensed financial statements in accordance with GAAP requires our management to make estimates and assumptions that affect the amounts reported on our unaudited 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 Accounting Policies

3 Months Ended

Mar. 31, 2019

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 income (loss) consists of unrealized gains and losses on marketable securities and foreign currency.

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 shares and common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of outstanding stock options, unvested restricted stock awards, outstanding warrants and employee stock purchase plan rights.

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, outstanding stock options, unvested restricted stock awards, outstanding warrants and employee stock purchase plan rights are excluded from the calculation of diluted net loss per common share for the periods presented, 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, in thousands:

	Three Months Ended March 31,
	2019		2018
Stock options		4,333		3,011
Unvested restricted stock awards		—		498
Warrant		34		34
Employee stock purchase plan rights		16		—
Total		4,383		3,543

Recent Accounting Pronouncements

In February 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, 2016-02, Leases (Topic 842), which amended prior accounting standards for leases. ASU 2016-02 requires lessees to recognize right-of-use, or ROU, assets and lease liabilities on the balance sheet and requires expanded disclosures about leasing arrangements. Subsequently, the FASB issued ASU 2018-11, Leases (Topic 842): Targeted Improvements. ASU 2018-11 provides entities another option for transition, allowing entities to not apply the new standard in the comparative periods they present in the financial statements in the year of adoption. We adopted the new lease standard on January 1, 2019, using the alternative modified transition method provided by ASU 2018-11 and did not retrospectively apply to prior periods. We elected the “package of practical expedients” permitted under the transition which allows us not to reassess our historical assessment of whether existing contracts are or contain a lease and the classification of existing lease arrangements, and to calculate the present value of the fixed payments without performing an allocation of lease and non-lease components. As a result of the adoption of the new standard, we recognized operating lease ROU assets and operating lease liabilities of $0.6 million on our unaudited condensed balance sheet as of January 1, 2019. ROU assets are recorded in Other Long-Term Assets and Other Long-Term Assets, Related Party on our unaudited condensed balance sheets. Current and non-current lease liabilities are recorded in Accounts Payable and Accrued Expenses and Accounts Payable and Accrued Expenses, Related Party and Other Long-Term Liabilities and Other Long-Term Liabilities, Related Party, respectively, on our unaudited condensed balance sheets. The adoption of the new lease standard had no impact on our accumulated deficit. The adoption of the new lease standard did not have a material impact on our results of operations and cash flows. See Note 6, Leases, for further details.

In June 2018, the FASB issued ASU 2018-07, Improvements to Nonemployee Share-Based Payment Accounting (Topic 718), which expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. The new guidance is intended to simplify aspects of share-based compensation issued to nonemployees by aligning the accounting for share-based payment awards issued to employees and nonemployees as it relates to measurement date and impact of performance conditions. This standard is effective for fiscal years beginning after December 15, 2018, and interim periods within those annual periods. We adopted ASU 2018-07 on January 1, 2019. The adoption of ASU 2018-07 did not have a material impact on our unaudited condensed financial statements.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses: Measurement of Credit Losses on Financial Instruments, which changes the impairment model for most financial assets and certain other instruments. For trade receivables and other instruments, entities will be required to use a new forward-looking expected loss model that generally will result in the earlier recognition of allowances for losses. For available-for-sale debt securities with unrealized losses, the losses will be recognized as allowances rather than as reductions in the amortized cost of the securities. This guidance is effective for annual reporting periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted only as of annual reporting periods beginning after December 15, 2018. We are currently evaluating the timing and impact of the adoption of ASU 2016-13 on our unaudited condensed financial statements or related financial statement disclosures.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. The new guidance modifies the disclosure requirements on fair value measurements in Topic 820. The amendments in ASU 2018-13 are effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. We are currently evaluating the timing and impact of the adoption of ASU 2018-13 on our unaudited condensed financial statements or related financial statement disclosures.

Investments

3 Months Ended

Mar. 31, 2019

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 and commercial paper. Available-for-sale securities are classified as part of either cash and cash equivalents or short-term investments on our unaudited condensed balance sheets.

The following tables summarize, by major security type, our investments that are measured at fair value on a recurring basis, in thousands:

		As of March 31, 2019
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market funds	1 or less	$	13,590	$	—	$	—		$	13,590

Short-term investments:
Corporate debt securities	2 or less		84,066		45		(12	)		84,099
U.S. Treasury securities	1 or less		44,763		11		(26	)		44,748
Commercial paper	1 or less		18,900		—		—			18,900
Total short-term investments			147,729		56		(38	)		147,747
Total		$	161,319	$	56	$	(38	)	$	161,337

		As of December 31, 2018
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market funds	1 or less	$	8,508	$	—	$	—		$	8,508

Short-term investments:
Corporate debt securities	1 or less		56,779		6		(77	)		56,708
U.S. Treasury securities	1 or less		39,780		—		(57	)		39,723
Commercial paper	1 or less		66,435		—		—			66,435
Total short-term investments			162,994		6		(134	)		162,866
Total		$	171,502	$	6	$	(134	)	$	171,374

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 March 31, 2019, $142.8 million of our short-term investments had maturities less than one year, and $5.0 million had maturities between one to two years. Realized gains and losses were de minimus for the three months ended March 31, 2019. As of March 31, 2019, $55.1 million of our marketable securities were in immaterial gross unrealized loss positions.

At each reporting date, we perform an evaluation of our marketable securities to determine if any unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include (i) the financial strength of the issuing institution, (ii) the length of time and extent for which fair value has been less than the cost basis and (iii) our intent and ability to hold our investments in unrealized loss positions until their amortized cost basis has been recovered. Based on our evaluation, we determined that our unrealized losses were not other-than-temporary at March 31, 2019 and December 31, 2018.

Fair Value Measurements

3 Months Ended

Mar. 31, 2019

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 and commercial paper, 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 March 31, 2019
	Balance		Level 1		Level 2
Cash equivalents:
Money market funds	$	13,590	$	13,590	$	—

Short-term investments:
Corporate debt securities		84,099	—			84,099
U.S. Treasury securities		44,748		44,748		—
Commercial paper		18,900		—		18,900
Total short-term investments		147,747		44,748		102,999
Total	$	161,337	$	58,338	$	102,999

	As of December 31, 2018
	Balance		Level 1		Level 2
Cash equivalents:
Money market funds	$	8,508	$	8,508	$	—

Short-term investments:
Corporate debt securities		56,708		—		56,708
U.S. Treasury securities		39,723		39,723		—
Commercial paper		66,435		—		66,435
Total short-term investments		162,866		39,723		123,143
Total	$	171,374	$	48,231	$	123,143

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.

Accounts Payable and Accrued Liabilities

3 Months Ended

Mar. 31, 2019

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:

	March 31, 2019		December 31, 2018
Accounts payable	$	3,074	$	3,890
Accrued research and development expenses		5,943		5,550
Accrued compensation and benefits		1,574		3,437
Other accrued expenses		1,191		508
Total accounts payable and accrued expenses	$	11,782	$	13,385

Leases

3 Months Ended

Mar. 31, 2019

Leases [Abstract]

Leases

6. Leases

We determine if an arrangement is a lease at inception. For operating leases with an initial term greater than 12 months, we recognize operating lease ROU assets and operating lease liabilities based on the present value of lease payments over the lease term at commencement date. Operating lease ROU assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms may include options to extend or terminate when we are reasonably certain that the option will be exercised. For our operating leases, we generally cannot determine the interest rate implicit in the lease, in which case we use our incremental borrowing rate as the discount rate for the lease. We estimate our incremental borrowing rate for our operating leases based on what we would normally pay to borrow on a collateralized basis over a similar term for an amount equal to the lease payments. Operating lease expense is recognized on a straight-line basis over the lease term.

If a lease is modified, the modified contract is evaluated to determine whether it is or contains a lease. If a lease continues to exist, the lease modification is determined to be a separate contract when the modification grants the lessee an additional right of use that is not included in the original lease and the lease payments increase commensurate with the standalone price for the additional ROU. The lease modification that results in a separate contract will be accounted in the same manner as a new lease. For a modification that is not a separate contract, we reassess the lease classification using the modified terms and conditions and the facts and circumstances as of the effective date of the modification and recognize the amount of the remeasurement of the lease liability for the modified lease as an adjustment to the corresponding ROU asset.

We have a sublease with a related party for office space in San Diego, California and a lease for office space in Cambridge, Massachusetts, that existed before January 1, 2019 and were classified as operating leases. In March 2019, the sublease was amended to extend the expiration date from October 31, 2019 to April 30, 2020 with the monthly rent increased from approximately $16,000 to approximately $24,000 per month effective November 1, 2019, see Note 8, Related Party Transactions for further details of the sublease. We determined the sublease amendment did not modify the ROU asset and, therefore, was not a separate contract. Accordingly, we reassessed the lease classification and concluded the operating lease classification remained appropriate. The modified lease terms were included in determining the present value of lease payments for the sublease at the modification date. As such, we recognized an adjustment of approximately $0.1 million as an increase to the sublease liability and ROU asset. We do not have any new operating leases nor any finance leases as of March 31, 2019.

Operating lease expense was as follows, in thousands:

	Three Months Ended
	March 31, 2019
Operating lease cost	$	68
Operating lease cost, related party		58
Total operating lease costs	$	126

Supplemental cash flow information related to our operating leases was as follows, in thousands:

	Three Months Ended
	March 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	67
Operating cash flows from operating leases, related party		49
Total cash paid for amounts included in the measurement of lease liabilities	$	116

ROU assets obtained in exchange for operating lease liabilities	$	61
ROU assets obtained in exchange for operating lease liabilities, related party		57
Total ROU assets obtained in exchange for operating lease liabilities	$	118

Supplemental balance sheet information related to our operating leases was as follows, in thousands (except lease term and discount rate):

	March 31, 2019
Operating lease ROU assets	$	345
Operating lease ROU assets, related party		243
Total operating lease ROU assets	$	588

Current lease liabilities	$	256
Current lease liabilities, related party		228
Non-current lease liabilities		90
Non-current lease liabilities, related party		24
Total operating lease liabilities	$	598

Weighted-average remaining lease term (in years)	1.2
Weighted-average discount rate		6.5	%

Maturities of lease liabilities are as follows, in thousands:

Year Ending December 31,
2019 (remaining)	$	369
2020		256
Total lease payments		625
Less: imputed interest		(27	)
Total operating lease liabilities	$	598

Share-Based Compensation

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-Based Compensation

7. Share-Based Compensation

The following table summarizes share-based compensation expense for all share-based compensation arrangements, in thousands:

	Three Months Ended March 31,
	2019		2018
Research and development	$	797	$	1,439
General and administrative		1,472		740
Total share-based compensation expense	$	2,269	$	2,179

As of March 31, 2019, unrecognized compensation costs related to employee stock options was approximately $26.9 million, which is expected to be recognized over a weighted average period of approximately 3.0 years.

Related Party Transactions

3 Months Ended

Mar. 31, 2019

Related Party Transactions

8. Related Party Transactions

Our president and chief executive officer is also the sole managing member of Araxes Pharma LLC, or Araxes, and is a significant stockholder of each of us and Araxes. The following is a summary of related party transactions for the three months ended March 31, 2019 and 2018:

•

Facility Sublease

We sublease office space in San Diego, California from Wellspring Biosciences, Inc., or Wellspring, a wholly owned subsidiary of Araxes. The sublease commenced in June 2017 and would have expired on October 31, 2019. In March 2019, the sublease was amended to extend until April 30, 2020, and the monthly rent increased to approximately $24,000 per month effective November 1, 2019, corresponding to the increase in Wellspring’s monthly rent. For the three months ended March 31, 2019 and 2018, rent expense, including operating costs, related to our sublease was approximately $0.1 million in both periods, as further discussed in Note 6, Leases.

•

Management Fees

We have a management services agreement with Araxes pursuant to which Araxes pays us monthly fees for management services calculated based on costs incurred by us in the provision of services to Araxes, plus a reasonable mark-up. For the three months ended March 31, 2019 and 2018, we recorded approximately $0.1 million and $0.2 million, respectively, in management fee income. 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 $374,000, plus actual expenses as reasonably incurred. The initial term of this 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 March 31, 2019 and 2018, we recorded reimbursements of approximately $0.1 million in both periods for research and development services provided to Araxes, which was recorded as a reduction to research and development expenses on our unaudited condensed statements of operations and comprehensive loss. As of March 31, 2019 and December 31, 2018, approximately $0.2 million in both periods related to management fees and reimbursements of research and development services are included in accounts receivable, related party on our unaudited condensed balance sheets.

•

Services Agreement

We have a services agreement with Wellspring pursuant to which we pay Wellspring for research and development services provided to us in 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 March 31, 2019 and 2018, we recognized approximately $0.1 million and $0.3 million, respectively, from research and development services provided to us under this agreement as research and development expense, related party on our unaudited condensed statements of operations and comprehensive loss. As of March 31, 2019 and December 31, 2018, approximately $0.1 million and $0.2 million, respectively, related to research and development services under this agreement are included in accounts payable and accrued expenses, related party on our unaudited condensed balance sheets.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2019

Accounting Policies [Abstract]

Comprehensive Loss

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, in thousands:

	Three Months Ended March 31,
	2019		2018
Stock options		4,333		3,011
Unvested restricted stock awards		—		498
Warrant		34		34
Employee stock purchase plan rights		16		—
Total		4,383		3,543

Recent Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2019

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, in thousands:

	Three Months Ended March 31,
	2019		2018
Stock options		4,333		3,011
Unvested restricted stock awards		—		498
Warrant		34		34
Employee stock purchase plan rights		16		—
Total		4,383		3,543

Investments (Tables)

3 Months Ended

Mar. 31, 2019

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, in thousands:

		As of March 31, 2019
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market funds	1 or less	$	13,590	$	—	$	—		$	13,590

Short-term investments:
Corporate debt securities	2 or less		84,066		45		(12	)		84,099
U.S. Treasury securities	1 or less		44,763		11		(26	)		44,748
Commercial paper	1 or less		18,900		—		—			18,900
Total short-term investments			147,729		56		(38	)		147,747
Total		$	161,319	$	56	$	(38	)	$	161,337

		As of December 31, 2018
	Maturities (years)	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Cash equivalents:
Money market funds	1 or less	$	8,508	$	—	$	—		$	8,508

Short-term investments:
Corporate debt securities	1 or less		56,779		6		(77	)		56,708
U.S. Treasury securities	1 or less		39,780		—		(57	)		39,723
Commercial paper	1 or less		66,435		—		—			66,435
Total short-term investments			162,994		6		(134	)		162,866
Total		$	171,502	$	6	$	(134	)	$	171,374

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2019

Fair Value Disclosures [Abstract]

Schedule Of Fair Value Measurements, By Major Security Type

	As of March 31, 2019
	Balance		Level 1		Level 2
Cash equivalents:
Money market funds	$	13,590	$	13,590	$	—

Short-term investments:
Corporate debt securities		84,099	—			84,099
U.S. Treasury securities		44,748		44,748		—
Commercial paper		18,900		—		18,900
Total short-term investments		147,747		44,748		102,999
Total	$	161,337	$	58,338	$	102,999

	As of December 31, 2018
	Balance		Level 1		Level 2
Cash equivalents:
Money market funds	$	8,508	$	8,508	$	—

Short-term investments:
Corporate debt securities		56,708		—		56,708
U.S. Treasury securities		39,723		39,723		—
Commercial paper		66,435		—		66,435
Total short-term investments		162,866		39,723		123,143
Total	$	171,374	$	48,231	$	123,143

Accounts Payable and Accrued Liabilities (Tables)

3 Months Ended

Mar. 31, 2019

Payables And Accruals [Abstract]

Accounts Payable and Accrued Liabilities

Accounts payable and accrued liabilities consisted of the following, in thousands:

	March 31, 2019		December 31, 2018
Accounts payable	$	3,074	$	3,890
Accrued research and development expenses		5,943		5,550
Accrued compensation and benefits		1,574		3,437
Other accrued expenses		1,191		508
Total accounts payable and accrued expenses	$	11,782	$	13,385

Leases (Tables)

3 Months Ended

Mar. 31, 2019

Leases [Abstract]

Schedule of Operating Lease Expense

Operating lease expense was as follows, in thousands:

	Three Months Ended
	March 31, 2019
Operating lease cost	$	68
Operating lease cost, related party		58
Total operating lease costs	$	126

Schedule of Supplemental Cash Flow Information Related to Operating Leases

Supplemental cash flow information related to our operating leases was as follows, in thousands:

	Three Months Ended
	March 31, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	67
Operating cash flows from operating leases, related party		49
Total cash paid for amounts included in the measurement of lease liabilities	$	116

ROU assets obtained in exchange for operating lease liabilities	$	61
ROU assets obtained in exchange for operating lease liabilities, related party		57
Total ROU assets obtained in exchange for operating lease liabilities	$	118

Schedule of Supplemental Balance Sheet Information Related to Operating Leases

Supplemental balance sheet information related to our operating leases was as follows, in thousands (except lease term and discount rate):

	March 31, 2019
Operating lease ROU assets	$	345
Operating lease ROU assets, related party		243
Total operating lease ROU assets	$	588

Current lease liabilities	$	256
Current lease liabilities, related party		228
Non-current lease liabilities		90
Non-current lease liabilities, related party		24
Total operating lease liabilities	$	598

Weighted-average remaining lease term (in years)	1.2
Weighted-average discount rate		6.5	%

Schedule of Maturities of Lease Liabilities

Maturities of lease liabilities are as follows, in thousands:

Year Ending December 31,
2019 (remaining)	$	369
2020		256
Total lease payments		625
Less: imputed interest		(27	)
Total operating lease liabilities	$	598

Share-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Share-based Compensation Expense

The following table summarizes share-based compensation expense for all share-based compensation arrangements, in thousands:

	Three Months Ended March 31,
	2019		2018
Research and development	$	797	$	1,439
General and administrative		1,472		740
Total share-based compensation expense	$	2,269	$	2,179

Summary of Significant Accounting Policies - Summary of Number of Potentially Dilutive Securities Excluded from Calculation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	4,383	3,543
Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	4,333	3,011
Unvested Restricted Stock Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities		498
Warrant
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	34	34
Employee Stock Purchase Plan Rights
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities	16

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Accounting Policies [Abstract]
Operating leases, right of use asset	$ 588	$ 600
Operating leases, liability	$ 598	$ 600

Investments - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Mar. 31, 2019

Dec. 31, 2018

Schedule Of Available For Sale Securities [Line Items]

Fair Value Measurements on Recurring Basis

$ 147,747

$ 162,866

^[1]

Schedule Of Available For Sale Securities [Line Items]

Short-term investments, Unrealized Gains

147,729

162,994

Short-term investments, Unrealized Losses

(38)

(134)

Cash equivalents and Short-term investments, Amortized Cost

147,747

162,866

161,319

171,502

Cash equivalents and Short-term investments, Unrealized Gains

Cash equivalents and Short-term investments, Unrealized Losses

(38)

(134)

Cash equivalents and Short-term investments, Fair Value

$ 161,337

$ 171,374

Fair Value Measurements on Recurring Basis | Money Market Funds

Schedule Of Available For Sale Securities [Line Items]

Cash equivalents, Amortized Cost

1 or less

$ 13,590

$ 8,508

Cash equivalents, Fair Value

$ 13,590

$ 8,508

Fair Value Measurements on Recurring Basis | Corporate Debt Securities

Schedule Of Available For Sale Securities [Line Items]

2 or less

1 or less

Short-term investments, Unrealized Gains

$ 84,066

$ 56,779

Short-term investments, Unrealized Losses

(12)

(77)

Fair Value Measurements on Recurring Basis | U.S. Treasury Securities

$ 84,099

$ 56,708

Schedule Of Available For Sale Securities [Line Items]

1 or less

Short-term investments, Unrealized Gains

$ 44,763

$ 39,780

Short-term investments, Unrealized Losses

(26)

(57)

Fair Value Measurements on Recurring Basis | Commercial Paper

$ 44,748

$ 39,723

Schedule Of Available For Sale Securities [Line Items]

1 or less

$ 18,900

$ 66,435

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

$ 18,900

$ 66,435

[1]	The balance sheet data at December 31, 2018 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 Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
Investments - Additional Information (Detail) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Investments All Other Investments [Abstract]
Marketable securities gross unrealized loss positions	$ 55,100,000
Short-term investments maturities, description	As of March 31, 2019, $142.8 million of our short-term investments had maturities less than one year, and $5.0 million had maturities between one to two years
Short-term investments with maturities less than one year	$ 142,800,000
Short-term investments with maturities between one to two years	5,000,000
Unrealized losses other-than-temporary	$ 0	$ 0

Fair Value Measurements - Fair Values of Investment Securities (Detail) - USD ($)
$ in Thousands

Mar. 31, 2019

Dec. 31, 2018

Fair Value Measurements on Recurring Basis

$ 147,747

$ 162,866

^[1]

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Cash equivalents and short-term investments

147,747

162,866

161,337

171,374

Fair Value Measurements on Recurring Basis | Level 1

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Cash equivalents and short-term investments

44,748

39,723

58,338

48,231

Fair Value Measurements on Recurring Basis | Level 2

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Cash equivalents and short-term investments

102,999

123,143

102,999

123,143

Fair Value Measurements on Recurring Basis | Money Market Funds

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Cash equivalents

13,590

8,508

Fair Value Measurements on Recurring Basis | Money Market Funds | Level 1

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Cash equivalents

13,590

8,508

Fair Value Measurements on Recurring Basis | Corporate Debt Securities

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Fair Value Measurements on Recurring Basis | Corporate Debt Securities | Level 2

84,099

56,708

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Fair Value Measurements on Recurring Basis | U.S. Treasury Securities

84,099

56,708

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Fair Value Measurements on Recurring Basis | U.S. Treasury Securities | Level 1

44,748

39,723

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Fair Value Measurements on Recurring Basis | Commercial Paper

44,748

39,723

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Fair Value Measurements on Recurring Basis | Commercial Paper | Level 2

18,900

66,435

Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]

Accrued research and development expenses

$ 18,900

$ 66,435

[1]	The balance sheet data at December 31, 2018 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 Liabilities (Detail) - USD ($)
$ in Thousands

Mar. 31, 2019

Dec. 31, 2018

Payables And Accruals [Abstract]

Accounts payable

$ 3,074

$ 3,890

5,943

5,550

Accrued compensation and benefits

1,574

3,437

Other accrued expenses

1,191

508

Total accounts payable and accrued expenses

$ 11,782

$ 13,385

^[1]

[1]	The balance sheet data at December 31, 2018 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.

Leases - Additional Information (Detail) - USD ($)			1 Months Ended
Leases - Additional Information (Detail) - USD ($)	Nov. 01, 2019	Jun. 01, 2017	Mar. 31, 2019	Jan. 01, 2019
Lessee Lease Description [Line Items]
Increase in operating lease ROU asset			$ 588,000	$ 600,000
Wellspring Biosciences Inc \| San Diego, California
Lessee Lease Description [Line Items]
Sublease expiration date		Oct. 31, 2019
Sublease extended date			Apr. 30, 2020
Amended sublease effective date			Nov. 01, 2019
Increase in sublease liability			$ 100,000
Increase in operating lease ROU asset			$ 100,000
Wellspring Biosciences Inc \| San Diego, California \| Monthly
Lessee Lease Description [Line Items]
Rent expense		$ 16,000
Wellspring Biosciences Inc \| San Diego, California \| Monthly \| Scenario Forecast
Lessee Lease Description [Line Items]
Rent expense	$ 24,000

Leases - Schedule of Operating Lease Expense (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Lessee Lease Description [Line Items]
Operating lease cost	$ 126
Cambridge. MA Office Lease
Lessee Lease Description [Line Items]
Operating lease cost	68
Wellspring Biosciences Inc
Lessee Lease Description [Line Items]
Operating lease cost	$ 58

Leases - Schedule of Supplemental Cash Flow Information Related to Operating Leases (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 116
ROU assets obtained in exchange for operating lease liabilities	118
Cambridge. MA Office Lease
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	67
ROU assets obtained in exchange for operating lease liabilities	61
Wellspring Biosciences Inc
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	49
ROU assets obtained in exchange for operating lease liabilities	$ 57

Leases - Schedule of Supplemental Balance Sheet Information Related to Operating Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Lessee Lease Description [Line Items]
Operating lease ROU assets	$ 588	$ 600
Total operating lease liabilities	$ 598	$ 600
Weighted-average remaining lease term (in years)	1 year 2 months 12 days
Weighted-average discount rate	6.50%
Cambridge. MA Office Lease
Lessee Lease Description [Line Items]
Operating lease ROU assets	$ 345
Current lease liabilities	256
Non-current lease liabilities	90
Wellspring Biosciences Inc
Lessee Lease Description [Line Items]
Operating lease ROU assets	243
Current lease liabilities, related party	228
Non-current lease liabilities, related party	$ 24

Leases - Schedule of Maturities of Lease Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019
Leases [Abstract]
2019 (remaining)	$ 369
2020	256
Total lease payments	625
Less: imputed interest	(27)
Total operating lease liabilities	$ 598	$ 600

Share-Based Compensation - Summary of Share-based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 2,269	$ 2,179
Research and development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	797	1,439
General and administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense	$ 1,472	$ 740

Share-Based Compensation - Additional Information (Detail) - Employee Stock Option $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized Expense	$ 26.9
Weighted average service period	3 years

Related Party Transactions - Additional Information (Detail) - USD ($)

1 Months Ended

3 Months Ended

Jan. 02, 2019

Jun. 01, 2017

Oct. 01, 2014

Mar. 31, 2019

Mar. 31, 2018

Dec. 31, 2018

Management fee income

$ 126,000

$ 195,000

Research and development, related party

$ 179,000

179,000

$ 224,000

^[1]

53,000

299,000

Accounts payable and accrued expenses, related party

361,000

$ 361,000

230,000

^[1]

Wellspring Biosciences Inc | Service Agreements

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 expense payment, description

Research and development, related party

$ 100,000

300,000

Accounts payable and accrued expenses, related party

100,000

$ 100,000

200,000

Araxes Pharma LLC | Management Fees

Research and development services 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 $374,000, plus actual expenses as reasonably incurred. The initial term of this 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.

Management fee income

$ 100,000

200,000

Service Agreement for research and development

$ 374,000

Agreement expiration date

Dec. 31, 2015

Agreement termination notice period

30 days

Amount received on research and development services

100,000