Kura Oncology (KURA) S-1 17 Apr 15 IPO registration Financial data

Document_and_Entity_Informatio

Document and Entity Information	12 Months Ended
	Dec. 31, 2014
Document Information [Line Items]
Document Type	S-1
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Entity Registrant Name	KURA ONCOLOGY, INC.
Entity Central Index Key	1422143
Entity Filer Category	Smaller Reporting Company

Balance_Sheets

Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash	$1,123,864
Accounts receivable, related party	30,139
Prepaid expenses	42,562
Total current assets	1,196,565
Property and equipment, net	26,646
Prepaid expenses	149,949
Other long-term assets, related party	4,680
Total assets	1,377,840
Current liabilities:
Accounts payable and accrued expenses	832,933
Accounts payable	225,642
Accounts payable, related party	134,563
Accrued expenses	567,887
Convertible notes payable, related party, current	2,035,565
Other current liabilities	12,786
Total current liabilities	3,015,847
Convertible notes payable, related party	493,418
Other long-term liabilities	1,294,559
Other long-term liabilities, related party	7,500
Total liabilities	4,811,324
Commitments and contingencies (Note 8)
Stockholders' deficit
Common stock, $0.0001 par value; 100,000,000 shares authorized; 5,000,000 shares issued and outstanding	821
Additional paid-in capital	236,961
Accumulated deficit	-3,671,266
Total stockholders' deficit	-3,433,484
Total liabilities and stockholders' deficit	1,377,840
Zeta Acquisition Corp III
Current assets:
Cash	5,613	6,568
Prepaid expenses		2,500
Total assets	5,613	9,068
Current liabilities:
Accounts payable	2,402	350
Accrued interest	24,002	17,175
Accrued expenses	8,900	5,500
Convertible notes payable, related party, current	125,000	110,000
Total liabilities	160,304	133,025
Stockholders' deficit
Preferred stock, $0.0001 par value; 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.0001 par value; 100,000,000 shares authorized; 5,000,000 shares issued and outstanding	500	500
Additional paid-in capital	49,500	49,500
Deficit accumulated during the development stage	-204,691	-173,957
Total stockholders' deficit	-154,691	-123,957
Total liabilities and stockholders' deficit	$5,613	$9,068

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Common stock, par value	$0.00
Common stock, shares authorized	50,000,000
Common stock, shares issued	9,887,000
Common stock, shares outstanding	821,252
Common stock, shares repurchase	9,065,748
Zeta Acquisition Corp III
Preferred stock, par value	$0.00	$0.00
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	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	5,000,000	5,000,000
Common stock, shares outstanding	5,000,000	5,000,000

Statements_of_Operations

Statements of Operations (USD $)	4 Months Ended	12 Months Ended		85 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Operating expenses:
Research and development	$2,028,227
Total operating expenses	3,934,147
General and administrative	1,261,621
Other income (expense):
Management fee income, related party	300,000
Interest expense, related party	-37,119
Total other income	262,881
Net loss	-3,671,266
Net loss per basic and diluted common share	($12.99)
Weighted average number of shares used in computing net loss per share, basic and diluted	282,613
Related party
Operating expenses:
Research and development	624,565
General and administrative	19,734
Zeta Acquisition Corp III
Operating expenses:
Formation costs				15,643
General and administrative		23,907	22,734	165,046
Operating loss		-23,907	-22,734	-180,689
Other income (expense):
Interest expense		6,827	5,877	24,002
Net loss		($30,734)	($28,611)	($204,691)
Net loss per basic and diluted common share		($0.01)	($0.01)	($0.04)
Weighted average number of shares used in computing net loss per share, basic and diluted		5,000,000	5,000,000	4,946,195

Statements_of_Stockholders_Equ

Statements of Stockholders' Equity (Deficit) (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Zeta Acquisition Corp III	Zeta Acquisition Corp III	Zeta Acquisition Corp III	Zeta Acquisition Corp III
						Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Beginning balance at Dec. 31, 2006
Issuance of common stock on December 14, 2007 at $0.01 per share					$50,000	$500	$49,500
Issuance of common stock on December 14, 2007 at $0.01 per share (in shares)					5,000,000	5,000,000
Net loss					-14,977			-14,977
Ending Balance at Dec. 31, 2007					35,023	500	49,500	-14,977
Ending Balance (in shares) at Dec. 31, 2007						5,000,000
Beginning balance at Nov. 15, 2007
Net loss					-204,691
Ending Balance at Dec. 31, 2014					-154,691	500	49,500
Ending Balance (in shares) at Dec. 31, 2014						5,000,000
Beginning balance at Dec. 31, 2007					35,023			-14,977
Net loss					-33,623			-33,623
Ending Balance at Dec. 31, 2008					1,400	500	49,500	-48,600
Ending Balance (in shares) at Dec. 31, 2008						5,000,000
Net loss					-19,996			-19,996
Ending Balance at Dec. 31, 2009					-18,596	500	49,500	-68,596
Ending Balance (in shares) at Dec. 31, 2009						5,000,000
Net loss					-22,395			-22,395
Ending Balance at Dec. 31, 2010					-40,991	500	49,500	-90,991
Ending Balance (in shares) at Dec. 31, 2010						5,000,000
Net loss					-27,040			-27,040
Ending Balance at Dec. 31, 2011					-68,031	500	49,500	-118,031
Ending Balance (in shares) at Dec. 31, 2011						5,000,000
Net loss					-27,315			-27,315
Ending Balance at Dec. 31, 2012					-95,346	500	49,500	-145,346
Ending Balance (in shares) at Dec. 31, 2012						5,000,000
Net loss					-28,611			-28,611
Ending Balance at Dec. 31, 2013					-123,957	500	49,500	-173,957
Ending Balance (in shares) at Dec. 31, 2013						5,000,000
Net loss					-30,734			-30,734
Ending Balance at Dec. 31, 2014					-154,691	500	49,500	-204,691
Ending Balance (in shares) at Dec. 31, 2014						5,000,000
Beginning balance at Aug. 29, 2014
Share-based compensation expense	236,618		236,618
Issuance of restricted stock awards	1,164	821	343
Issuance of restricted stock awards (in shares)		821,252
Net loss	-3,671,266			-3,671,266
Ending Balance at Dec. 31, 2014	($3,433,484)	$821	$236,961	($3,671,266)		$500	$49,500
Ending Balance (in shares) at Dec. 31, 2014		821,252				5,000,000

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	4 Months Ended	12 Months Ended		85 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Operating activities
Net loss	($3,671,266)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	236,618
Depreciation expense	1,466
Issuance of convertible note for acquisition of license	500,000
Changes in operating assets and liabilities:
Accounts receivable, related party	-30,139
Decrease in prepaid expenses	-42,562
Other long-term assets	-149,949
Other long-term assets, related party	-4,680
Accounts payable and accrued expenses	832,933
Accounts payable, related party	134,563
Accrued interest, related party	36,483
Other liabilities	1,307,345
Net cash used in operating activities	-849,188
Investing activities
Purchases of property and equipment	-28,112
Net cash used in investing activities	-28,112
Financing activities
Proceeds from issuance of related party convertible notes	2,000,000
Proceeds from the issuance of restricted stock awards	1,164
Net cash provided by financing activities	2,001,164
Net increase (decrease) in cash and cash equivalents	1,123,864
Cash and cash equivalents at end of period	1,123,864	1,123,864		1,123,864
Zeta Acquisition Corp III
Operating activities
Net loss		-30,734	-28,611	-204,691
Changes in operating assets and liabilities:
Decrease in prepaid expenses		2,500	1,000
Increase (decrease) in accounts payable		2,052	-1,500	2,402
Accrued interest, related party		6,827	5,877	24,002
Increase in accrued expenses		3,400		8,900
Net cash used in operating activities		-15,955	-23,234	-169,387
Financing activities
Proceeds from issuance of related party convertible notes		15,000	25,000	135,000
Payments on notes payable, stockholders				-10,000
Proceeds from issuance of common stock				50,000
Net cash provided by financing activities		15,000	25,000	175,000
Net increase (decrease) in cash and cash equivalents		-955	1,766	5,613
Cash and cash equivalents at beginning of period		6,568	4,802
Cash and cash equivalents at end of period	$5,613	$5,613	$6,568	$5,613

Statements_of_Stockholders_Equ1

Statements of Stockholders' Equity (Deficit) (Parenthetical) (Zeta Acquisition Corp III, USD $)	Dec. 31, 2007
Zeta Acquisition Corp III
Issuance of common stock, price per share	$0.01

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2014
Organization and Basis of Presentation	1. Organization and Basis of Presentation
	Kura Oncology, Inc. (the “Company”), a privately held company incorporated in Delaware, is a clinical stage biopharmaceutical company discovering and developing personalized therapeutics for the treatment of solid tumors and blood cancers. The Company focuses on the development of small molecule drug candidates that target cell signaling pathways that are important to driving the progression of certain cancers. The Company aims to employ molecular diagnostics to identify patients with cancers who are likely to benefit from our targeted drug candidates.
	From August 22, 2014 (inception) through December 31, 2014, the Company has devoted substantially all of its efforts to research, product development, raising capital, and building infrastructure. The Company has a limited operating history and the sales and income potential of the Company’s business and market are unproven. The Company has experienced net losses and negative cash flows from operating activities, and had an accumulated deficit of $3,671,266 as of December 31, 2014.
	The Company expects to continue to incur net losses into the foreseeable future. Successful transition to attaining profitable operations is dependent upon achieving a level of revenues adequate to support the Company’s cost structure. The Company plans to continue to fund its losses from operations and capital funding needs through future debt and equity financing or through collaborations or partnerships with other companies. If the Company is not able to secure adequate additional funding, the Company may be forced to make reductions in spending, liquidate assets where possible, or suspend or curtail planned programs. Any of these actions could materially harm the Company’s business, results of operations and future prospects. The Company believes that its existing cash resources will be sufficient to fund its operations through at least December 31, 2015.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies
	Use of Estimates
	The Company’s financial statements are prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). The preparation of the Company’s financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period.
	Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. All revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.
	Concentration of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits and limits its exposure to cash risk by placing its cash with credit quality rating financial institutions.
	Property and Equipment
	Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets which is three years for each asset class.
	Impairment of Long-Lived Assets
	The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. If such circumstances are determined to exist, an estimate of undiscounted future cash flows produced by the long-lived asset, including its eventual residual value, is compared to the carrying value to determine whether impairment exists. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written-down to their estimated fair values. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, the Company believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses through December 31, 2014.
	Convertible Notes and Derivative Accounting
	At inception, the Company performs an assessment of all embedded features of a debt instrument to determine if (1) such features should be bifurcated and separately accounted for, and (2) if bifurcation requirements are met, whether such features should be classified and accounted for as equity or liability. The fair value of the embedded feature is measured initially, included as a liability on the balance sheet, and remeasured each reporting period. Any changes in fair value are recorded in the statement of operations. The Company monitors, on an ongoing basis, whether events or circumstances could give rise to a change in its classification of embedded features.
	The Company accounts for its convertible notes, that may be settled in cash upon conversion (including partial cash settlement), by separating the liability and equity components of the instruments in a manner that reflects the Company’s nonconvertible debt borrowing rate. The Company determines the carrying amount of the liability component by measuring the fair value of similar debt instruments that do not have the conversion feature. If a similar debt instrument does not exist, the Company estimates the fair value by using assumptions that market participants would use in pricing a debt instrument, including market interest rates, credit standing, yield curves and volatilities. Determining the fair value of the debt component requires the use of accounting estimates and assumptions. These estimates and assumptions are judgmental in nature and could have a significant impact on the determination of the debt component and the associated non-cash interest expense.
	Deferred Rent
	Deferred rent consists of the difference between cash payments and the recognition of rent expense on a straight-line basis for the facilities the Company occupies. The Company’s lease for its facilities provides for fixed increases in minimum annual rental payments. The total amount of rental payments due over the lease term is being charged to rent expense ratably over the life of the lease. The Company’s deferred rent balance is contained within other long-term liabilities on the Company’s Balance Sheet.
	Research and Development Costs
	Research and development costs are expensed as incurred. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research activities on the Company’s behalf. Payments that the Company makes in connection with in-licensed technology for a particular research and development project that have no alternative future uses (in other research and development projects or otherwise) and therefore no separate economic values are expensed as research and development costs at the time such costs are incurred. As of December 31, 2014, the Company has no in-licensed technologies that have alternative future uses in research and development projects or otherwise.
	Patent Costs
	The Company expenses all costs as incurred in connection with patent applications, including direct application fees, and the legal and consulting expenses related to making such applications, and such costs are included in general and administrative expenses within the Company’s Statement of Operations and Comprehensive Loss.
	Share-Based Compensation
	Restricted stock awards are valued based on the fair value on the grant date. The fair value of restricted stock awards expected to vest are recognized and amortized on a straight-line basis over the requisite service period of the award, which is generally four years. Restricted stock awards granted to non-employees are recorded at their fair value on the earlier of the performance commitment date or the date the services required are completed and are marked to market during the service period. Non-employee restricted stock awards are remeasured and expensed as they vest based on the intrinsic value method.
	The Company’s equity incentive plan allows for the issuance of restricted stock awards to employees and non-employee consultants that may be subject to vesting. The unvested shares of any restricted stock awards are held in escrow as the stock award vests or until award holder termination, whichever occurs first. In the event of a termination, the Company has the right of repurchase, at its option, for the portion of unvested stock awards from the terminated award holder. The repurchase price for unvested stock awards will be the lower of (i) the fair market value of the shares of common stock on the date of repurchase or (ii) their original purchase price. For all unvested stock awards, a liability is established related to the cash received for the unvested portion of the stock award, which represents the Company’s obligation if all award holders were to be terminated, and is recorded within other long-term liabilities on the Company’s Balance Sheet.
	Income Taxes
	Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. For uncertain tax positions that meet “a more likely than not” threshold, the Company recognizes the benefit of uncertain tax positions in the financial statements.
	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized losses on investments. Net loss and comprehensive loss were the same for the period presented, therefore, a separate statement of comprehensive loss is not included in the accompanying financial statements.
	Segment Reporting
	Operating segments are components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker for purposes of making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States.
	Fair Value Measurements
	The Company categorizes its assets and liabilities measured at fair value in accordance with the authoritative accounting guidance that establishes a consistent framework for measuring fair value, and expands disclosures for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as the exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, 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.
	At December 31, 2014, the Company did not have financial assets that are measured at fair value on a recurring basis. The carrying amounts of the Company’s financial instruments, which include cash, prepaid expenses, accounts payable, accrued expenses and all related party amounts approximate their fair values at December 31, 2014, primarily due to their short-term nature. The Company believes the fair value of its convertible notes approximates their carrying value as of December 31, 2014. No transfers between levels have occurred during the periods presented. Liabilities measured at fair value on a recurring basis as of December 31, 2014 are as follows:
					Fair Value Measurements at December 31, 2014
			Balance as of		Quoted Prices		Significant		Significant
			December 31,		in Active		Other		Unobservable
			2014		Markets for		Observable		Inputs
					Identical Assets		Inputs		(Level 3)
					(Level 1)		(Level 2)
	Liabilities
	Embedded derivative liability (1)		$	196,000	$	—	$	—	$	196,000
	-1	The Company’s license agreement with the with The Regents of the University of California San Francisco (“UCSF”), further described in Note 7, provides for an indexed milestone payment upon the occurrence of a qualified preferred stock financing and a subsequent initial public offering or a change of control event, as defined in the agreement. The indexed milestone was determined to qualify as an embedded derivative liability requiring an estimate of fair value.
	The Company estimates the fair value of its derivative liabilities at the time of issuance and subsequent remeasurement at each reporting date using a probability model that considers the probability of achieving the events that would trigger such liabilities and the estimated time period the liabilities would be outstanding. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions can have a significant impact on the fair value of the derivative liabilities.
	The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs:
			Derivative
			Liabilities
	Balance at August 22, 2014 (Inception)		$	—
	Issuance of derivative liability (1)			196,000
	Change in fair value (2)			—
	Balance at December 31, 2014		$	196,000
	-1	The amount is included within research and development expenses on the Company’s Statement of Operations and Comprehensive Loss.
	-2	The license agreement was executed in November 2014 and no change in the valuation occurred between the execution date and December 31, 2014.
	Net Loss per Share
	Basic net loss per 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 under the Company’s equity plan. 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.
	Potentially dilutive securities, which includes unvested stock awards of 9,065,748 are excluded from the calculation of diluted net loss per share due to the anti-dilutive effect of the securities. In addition, the Company has $2,500,000 in principal of outstanding convertible promissory notes, issued in October and December 2014, that are convertible into common stock upon the occurrence of various future events at prices that are not determinable until the occurrence of those future events. As such, the Company has excluded these convertible notes payable from the calculation of diluted net loss per share.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2014
Recent Accounting Pronouncements	3. Recent Accounting Pronouncements
	From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) or other standard setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on our financial position or results of operations upon adoption.
	In May 2014, the FASB issued Accounting Standard Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606), which will replace numerous requirements in U.S. GAAP, including industry-specific requirements, and provide companies with a single revenue recognition model for recognizing revenue from contracts with customers. The core principle of the new standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The new standard will be effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period. The Company is currently evaluating the impact the adoption of this guidance will have on its Financial Statements and future operating results.
	In June 2014, the FASB issued ASU 2014-10, Development Stage Entities (Topic 915), an accounting standards update that removes the financial reporting distinction between development stage entities and other reporting entities from GAAP. In addition, the amendments eliminate the requirements for development stage entities to: (1) present inception-to-date information in the statements of income, cash flows, and shareholder equity, (2) label the financial statements as those of a development stage entity, (3) disclose a description of the development stage activities in which the entity is engaged, and disclose in the first year in which the entity is no longer a development stage entity that in prior years it had been in the development stage. The guidance is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2014. The Company’s early adoption of the standard eliminated the requirement to disclose inception-to-date information or incremental financial reporting requirements related to development stage entities and does not have any additional impact on the Company’s financial statement or disclosures.
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. The Company is currently evaluating the potential changes from this ASU to its future financial reporting and disclosures.

Property_and_equipment_net

Property and equipment, net	12 Months Ended
	Dec. 31, 2014
Property and equipment, net	4. Property and equipment, net
	Property and equipment consisted of the following:
		December 31,
		2014
	Computer equipment	$	25,862
	Software		2,250
			28,112
	Less: accumulated depreciation		(1,466	)
	Property and equipment, net	$	26,646

Accounts_payable_and_accrued_l

Accounts payable and accrued liabilities	12 Months Ended
	Dec. 31, 2014
Accounts payable and accrued liabilities	5. Accounts payable and accrued liabilities
	Accounts payable and accrued liabilities consisted of the following:
		December 31,
		2014
	Accounts payable	$	225,642
	Accrued expenses		567,887
	Accrued compensation and benefits		39,404
	Total accounts payable and accrued expenses	$	832,933

Notes_Payable

Notes Payable	12 Months Ended
	Dec. 31, 2014
Notes Payable	6. Notes Payable
	Araxes Convertible Note
	On October 8, 2014, the Company entered into a Note Purchase Agreement and Convertible Promissory Note with its affiliated company Araxes Pharma LLC (“Araxes”) under which Araxes provided a $2,000,000 loan in the form of a convertible promissory note. The note contains interest computed at a rate of 8%, compounded annually, with a maturity date of the earliest to occur of: (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default. Interest is due and payable on the maturity date. Prepayment of principal or interest is not allowed on the note without the prior written consent of Araxes. The note is automatically converted into such class of stock of the Company issued upon the completion of a qualified initial public offering (“IPO”) or upon the completion of a qualified financing, as defined in the agreement, in an amount equal to the total unpaid principal and interest divided by the price per share offered to the public in the qualified IPO or the price per share of the equity securities paid by other investors in a qualified financing. The Convertible Promissory Note contains customary events of default, and is recorded at its redemption amount, or at cost, within notes payable- related party, current on the Company’s Balance Sheet.
	Araxes Asset Purchase Agreement – Convertible Note
	As consideration for the patents acquired under the Araxes Asset Purchase agreement entered into on December 23, 2014 (described further in Note 7), Araxes issued a convertible promissory note equal to the purchase price of the patent rights of $500,000. The note contains interest computed at a rate of 8% with a maturity date of the earliest to occur: (i) of May 31, 2016 (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default. The note may not be prepaid. The note will automatically convert into such class of stock of the Company issued upon the completion of a qualified equity financing at the lowest per share price offered in the round. The Convertible Promissory Note contains customary events of default, and is recorded at its redemption amount within notes payable-related party, noncurrent on the Company’s Balance Sheet.
	Total notes payable and unamortized discount balances are as follows:
		December 31,
		2014
	Face value of convertible notes	$	2,500,000
	Accrued interest		36,483
	Debt issuance costs associated with fair value of derivative		(7,500	)
	Total	$	2,528,983
	Less: current portion		(2,035,565	)
	Total convertible notes, long-term	$	493,418

License_and_Asset_Purchase_Agr

License and Asset Purchase Agreements	12 Months Ended
	Dec. 31, 2014
License and Asset Purchase Agreements	7. License and Asset Purchase Agreements
	Janssen License Agreement
	On December 18, 2014, the Company entered into a license agreement with Janssen Pharmaceutica NV (“Janssen”), a foreign entity headquartered in Belgium and an affiliate of Johnson & Johnson, Inc., under which the Company received certain intellectual property rights related to tipifarnib in the field of oncology for a non-refundable $1,000,000 upfront license fee and payments upon achievement of certain development and sales-based milestones. Tipifarnib is a clinical stage compound and all ongoing development, regulatory and commercial work will be completed fully and at the sole expense of the Company. Under the license agreement, Janssen has a first right to negotiate for an exclusive license back from the Company to develop and commercialize tipifarnib on terms to be negotiated in good faith. Janssen may exercise this right of first negotiation during a 60-day period following delivery of clinical data as specified in the agreement.
	The agreement will terminate upon the last-to-expire patent rights or last-to-expire royalty term, or may be terminated by the Company with 180 days written notice of termination. Either party may terminate the agreement in the event of material breach of the agreement that is not cured within 45 days. Janssen may also terminate the agreement due to the Company’s lack of diligence that is not cured within a three-month period.
	The upfront license fee was paid in January 2015. Subsequent to such payment, in accordance with the agreement the Company entered into a convertible promissory note with Janssen’s affiliated company, Johnson & Johnson Innovation – JJDC, Inc. (“JJDC”) as described further in Note 13. Due to the long-term nature of the note, the full amount of the unpaid upfront fee is included within other long-term liabilities on the Company’s Balance Sheet as of December 31, 2014.
	The University of Michigan License Agreement
	On December 22, 2014, the Company entered into a license agreement with The Regents of The University of Michigan (“Michigan”) under which the Company received certain license rights for a non-refundable upfront license, annual maintenance fees and payments upon achievement of certain development and sales-based milestones. The licensed asset consists of a number of compounds, which are in the lead discovery/lead optimization phase. All future development, regulatory and commercial work on the asset will be completed fully and at the sole expense of the Company. Michigan retains the right to use the asset for non-commercial research, internal and/or educational purposes, with the right to grant the same limited rights to other non-profit research institutions. Furthermore, the agreement, as amended on March 3, 2015, stipulates contingent consideration for the issuance of shares equivalent to a set dollar value upon the occurrence of a qualified capital stock financing or a change of control event, as defined in the amended agreement, consistent with the terms issued to any future investors or the per share consideration to be received by other shareholders. See Note 13 for further discussion.
	The agreement will terminate upon the last-to-expire patent rights, or may be terminated by the Company at anytime with 90 days written notice of termination or terminated by Michigan upon a bankruptcy by the Company, payment failure by the Company that is not cured within 30 days or a material breach of the agreement by the Company that is not cured within 60 days.
	The University of San Francisco License Agreement
	On November 21, 2014, the Company entered into a license agreement with UCSF under which the Company received certain license rights. The agreement provided for an upfront payment as well as contingent milestone payments. Additionally, the agreement provides for a one-time indexed milestone payment upon the occurrence of an initial public offering or a change of control event following a qualified financing, as defined in the agreement. The indexed milestone was determined to qualify as an embedded derivative liability requiring an estimate of fair value. See Note 2 for further detail.
	Collectively, the license agreements with Janssen, Michigan and UCSF provided for non-refundable upfront payments totaling $1,075,000. Each of these license agreements was individually deemed an asset acquisition, which required the Company to expense the full upfront acquisition price due to the preliminary stage of development and no identified alternative future use upon the agreement execution date. The expense is included within research and development expenses in the Company’s Statement of Operations and Comprehensive Loss. In addition, the license agreements collectively provide for specified development, regulatory and sales-based milestone payments up to a total of $81,675,000 payable upon occurrence of each stated event, of which $1,175,000 relates to the initiation of certain development activities, $30,500,000 relates to the achievement of specified regulatory approvals for the first indication and up to $50,000,000 for the achievement of specified levels of product sales. Additional payments will be due for each subsequent indication if specified regulatory approvals are achieved. All milestone payments under the agreement will be recognized as research and development expense upon completion of the required events because the triggering events are not considered to be probable until they are achieved. As of December 31, 2014, the Company has not achieved any milestones under the agreements. Furthermore, if all the programs are successfully commercialized, the Company will be required to pay tiered royalties on annual net product sales ranging from the low single digits to the low teens, depending on the volume of sales and the respective agreement.
	Araxes Asset Purchase Agreement
	On December 23, 2014, the Company entered into an asset purchase agreement with Araxes under which the Company purchased certain early stage patent rights related to compounds in the field of oncology for a purchase price of $500,000 payable under a convertible promissory note. All ongoing development, regulatory and commercial work will be completed fully and at the sole expense of the Company. The agreement allows for contingent milestone payments of $9,650,000 throughout development and commercialization of the asset, of which $1,150,000 relates to the initiation of certain development activities, and $8,500,000 relates to the submission of certain regulatory filings and receipt of certain regulatory approvals. Additional payments will be due for each subsequent indication if specified regulatory approvals are achieved. The Company will recognize the milestones as expense when each event occurs. As of December 31, 2014, the Company has not achieved any milestones under the agreement. Furthermore, if the program is successfully commercialized, the Company will be required to pay tiered royalties on annual net product sales ranging in the low single digits, depending on the volume of sales.
	The transaction was deemed an asset acquisition, which required the Company to expense the full upfront acquisition price due to the preliminary stage of development and no identified alternative future use upon the agreement execution date and is included within research and development expenses, related party in the Company’s Statement of Operations and Comprehensive Loss. All additional milestone payments under the agreement will be recognized upon completion of the required events because the triggering events will not be considered to be probable until they are achieved.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies	8. Commitments and Contingencies
	On August 29, 2014, the Company entered into a sublease agreement (the “sublease”) with its affiliated company, Araxes, for office space for a monthly rent of $4,680 per month. The lease includes rent escalation of 3% per year. The lease was amended on December 18, 2014 for monthly rent of $4,820 per month and retrospectively applied from September 1, 2014 in accordance with the agreement. In addition to the base monthly rent, the Company is obligated to pay for operating expenses, taxes, insurance, and utilities applicable to the subleased property. The sublease will expire on August 30, 2016.
	On September 30, 2014, the Company entered into a lease agreement (the “lease”) with Regus for office space located in Cambridge, Massachusetts. The lease commenced on October 6, 2014 with monthly rent of $4,785 per month. Rent expense is recognized using the straight-line method over the term of the lease. In addition to the base monthly rent, the Company is obligated to pay for operating expenses, taxes, insurance and utilities applicable to the leased property. The lease will expire on October 31, 2016.
	Future minimum payments required under the leases as of December 31, 2014 are summarized as follows:
	Year Ending December 31,
	2015	$	111,062
	2016		87,573
	Total minimum lease payments	$	198,635
	Total lease expense for the period from August 22, 2014 (inception) to December 31, 2014 was $27,249.
	The Company is obligated to make a charitable gift of $285,000 to the Leukemia and Lymphoma Society in connection with the Michigan agreement described in Note 7 to be paid in three equal parts: the first part due in January 2015, the second part due in January 2016 and the final part due in January 2017. The full amount of the charitable gift has been accrued as of December 31, 2014.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity	9. Stockholders’ Equity
	Common Stock
	As of December 31, 2014, 1,113,000 shares were reserved for future issuance pursuant to shares authorized for future option grants. In addition, the Company has $2,500,000 in principal of outstanding convertible promissory notes, issued in October and December 2014, that are convertible into stock upon the occurrence of various future events at prices that are not determinable until the occurrence of those future events.
	Restricted Stock Awards
	In August 2014, the Company adopted the 2014 Equity Incentive Plan (“the 2014 Plan”). A total of 11,000,000 shares were initially reserved for issuance under the 2014 Plan. The 2014 Plan provides equity-based incentives in the form of stock awards to employees and other providers of services to the Company. The 2014 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, and other stock awards to eligible recipients. Recipients of incentive stock options shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to no less than the estimated fair market value of such stock on the date of grant. The maximum term of options to be granted under the Plan is ten years. No options were granted under the plan as of December 31, 2014.
	Restricted stock awards were granted at a price equal to estimated fair market value. The restricted stock awards generally vest over four years from the original vesting date, with certain grants subject to one-year cliff vesting. The vesting provisions of individual awards may vary as approved by the Company’s Board of Directors. In connection with the issuance of restricted common stock, the Company maintains a repurchase right where shares of restricted common stock are released from such repurchase right over a period of time of continued service by the recipient. The following is a summary of restricted share activity:
		Number of			Weighted
		Shares			Average
					Grant Date
					Fair Value
	Balance at August 22, 2014 (Inception)		—		$	—
	Granted		9,887,000		$	0.001
	Vested		(821,252	)
	Unvested at December 31, 2014		9,065,748		$	0.001
	Vested at December 31, 2014		821,252		$	0.001
	The shares purchased by the recipients pursuant to unvested restricted stock awards are not deemed, for accounting purposes, to be outstanding until those shares vest. The cash received in exchange for unvested shares related to stock awards granted is recorded as a liability for the early exercise of stock options on the accompanying balance sheet and will be transferred into common stock and additional paid-in capital as the shares vest. As of December 31, 2014, the Company recorded $12,786 of liability associated with shares issued with repurchase rights. As of December 31, 2014, there were 9,065,748 shares subject to repurchase, and 1,113,000 of common stock reserved for future stock awards under the 2014 Plan. The Company recognized $236,618 in share-based compensation expense related to the vested portion of the restricted stock awards granted to non-employees for the period from August 22, 2014 (inception) to December 31, 2014.

Notes_Payable_Stockholders

Notes Payable, Stockholders	12 Months Ended
	Dec. 31, 2014
Notes Payable, Stockholders	10. Related Party Transactions
	The Company’s president and chief executive officer is also the managing member of its affiliated company, Araxes. Four individuals are significant stockholders of each of the Company and Araxes. The following is a summary of all transactions with Araxes from August 22, 2014 (inception) to December 31, 2014.
	Convertible Promissory Notes
	As described in Note 6, the Company entered into a Note Purchase Agreement and Convertible Promissory Note with Araxes under which Araxes provided a $2,000,000 loan in the form of a convertible promissory note. The note is included within notes payable, related party, current on the Company’s Balance Sheet.
	Additionally, in conjunction with the asset purchase agreement with Araxes described in Note 7, the Company purchased assets for an upfront purchase price of $500,000 payable under a convertible promissory note. This amount is included with research and development expenses, related party on the Company’s Statement of Operations and Comprehensive Loss. Additionally, the note is included within notes payable, related party, noncurrent on the Company’s Balance Sheet.
	Facility Sublease
	As noted in Note 8, the Company subleases office space from Araxes for a monthly rent of $4,820 per month. In addition to the base monthly rent, the Company is obligated to pay for operating expenses, taxes, insurance, and utilities applicable to the subleased property. Rent expense related to this sublease for the period from August 22, 2014 (inception) to December 31, 2014 was $14,906. The sublease will expire on August 30, 2016.
	Management Fees
	The Company has a management services agreement with Araxes under which Araxes pays the Company a fixed $100,000 a month for management services. In addition, the agreement allows for Araxes to pay the Company an amount equal to the number of full time equivalents (“FTE”) performing collaboration services for Araxes, at an FTE rate of $350,000, plus actual expenses as reasonably incurred. The agreement has an initial term expiring on December 31, 2015 and 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 December 31, 2015 or the expiration of the then-renewal term.
	Services Agreement
	The Company has a services agreement with Araxes which allows for payment of research and development services provided to the Company of an amount equal to the number of FTE’s performing the services, at an FTE rate of $400,000, plus actual expenses as reasonably incurred. This services agreement has an initial term expiring on December 31, 2015 and 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 December 31, 2015 or the expiration of the then-renewal term.
Zeta Acquisition Corp III
Notes Payable, Stockholders	2. Notes Payable, Stockholders
	During 2014, various stockholders loaned the Company $15,000 and were issued unsecured promissory notes which bear interest at 6% and are due on demand. Similar stockholder loans amounted to $25,000 during 2013, $25,000 during 2012, $35,000 during 2010, and $25,000 in 2009. Interest of $24,002 and $17,175 was accrued and unpaid at December 31, 2014 and 2013, respectively.
	During 2007, the Company issued an unsecured promissory note to a stockholder and officer of the Company in the amount of $10,000. The note was non-interest bearing and was repaid from the proceeds of the sale of common stock.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2014
Employee Benefit Plan	11. Employee Benefit Plan
	The Company has a defined contribution 401(k) plan (the Plan) for all employees. Employees are eligible to participate in the Plan if they are at least 21 years of age or older. Under the terms of the Plan, employees may make voluntary contributions as a percentage of compensation.

Income_Tax_Disclosure

Income Tax Disclosure	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure	12. Income Taxes
	The Company was incorporated on August 22, 2014 and will file tax returns as prescribed by the tax laws of the jurisdictions in which it operates. In the normal course of business, the Company’s 2014 tax year will be subject to examination by the federal and state jurisdictions where applicable. The Company has not been, nor is it currently, under examination by the federal or any state tax authority.
	The Company’s effective income tax differs from the statutory federal rate of 34% at December 31, 2014 due to the following:
		Period from
		August 22, 2014
		(Inception) to
		December 31,
		2014
	Benefit for income taxes at statutory federal rate	$	(1,248,230	)
	State income tax (benefit), net of federal benefit		(224,752	)
	Share-based compensation		80,450
	Research and development tax credits		(28,288	)
	Other		13,307
	Valuation allowance		1,407,513
	Income tax expense	$	—
	Significant components of the Company’s deferred tax assets at December 31, 2014 are shown below:
		December 31, 2014
	Deferred tax assets
	Intangibles	$	731,622
	Net operating loss carryforwards		441,622
	Research and development tax credit carryforwards		28,288
	Accruals		204,608
	Other		1,373
	Total deferred tax assets		1,407,513
	Less valuation allowance		(1,407,513	)
	Net deferred tax assets	$	—
	At December 31, 2014, the Company had federal and state net operating loss carryforwards of $1,087,279 and $1,248,532 respectively. The federal and state loss carryforwards begin to expire in 2034, unless previously utilized. The Company also has federal and state research credit carryforwards of $17,919 and $15,710, respectively. The federal and Massachusetts research credits will begin expiring in 2034 and 2029, respectively, unless previously utilized. The California research credit will carryforward indefinitely.
	Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use existing deferred tax assets. Based on the weight of the evidence, including the Company’s limited existence and losses since inception, management has determined that it is more likely than not that the deferred tax assets will not be realized. A valuation allowance of $1,407,513 for the period ended December 31, 2014 has been established to offset the deferred tax assets as realization of such assets is uncertain.
	Pursuant to Internal Revenue Code (IRC) Sections 382 and 383, annual use of the Company’s net operating loss and research and development credit carryforwards may be limited in the event a cumulative change in ownership of more than 50% occurs within a three-year period. The Company has not completed an IRC Section 382/383 analysis regarding the limitation of net operating loss and research and development credit carryforwards. The Company does not expect this analysis to be completed within the next 12 months. Due to the existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will not impact the Company’s effective tax rate. Any carryforwards that will expire prior to utilization as a result of such limitations will be removed from deferred tax assets, with a corresponding reduction of the valuation allowance.
	The impact of an uncertain income tax position is recognized at the largest amount that is “more likely than not” to be sustained upon audit by the relevant taxing authority. An uncertain tax position will not be recognized if it has less than a 50% likelihood of being sustained. There are no unrecognized tax benefits included in the Company’s balance sheet at December 31, 2014. The Company’s practice is to recognize interest and penalties related to income tax matters in income tax expense. The Company has not recognized interest or penalties in its statements of operations for the period ended December 31, 2014.
	The Company does not expect that there will be a significant change in the unrecognized tax benefits over the next twelve months. Due to the existence of the valuation allowance, future changes in the Company’s unrecognized tax benefits will not impact the Company’s effective tax rate.
Zeta Acquisition Corp III
Income Tax Disclosure	5. Income Taxes
	The Company has reviewed its tax positions as of December 31, 2014 and 2013, and has not identified any positions that are uncertain. Income tax returns filed and to be filed for the years ended December 31, 2011, 2012, 2013, and 2014 are open to review by the Internal Revenue Service.
	The tax effects of temporary differences that give rise to significant portions of the Company’s net deferred tax asset at December 31, 2014 and 2013 are as follows:
		December 31,			December 31,
		2014			2013
	Deferred tax asset:
	Capitalized formation costs	$	61,400		$	53,300
	Net operating loss carryforward		8,200			5,800
	Valuation allowance		(69,600	)		(59,100	)
	Net deferred tax asset recognized	$	—		$	—
	A full valuation allowance has been recorded against the Company’s deferred tax asset because, based on the weight of available evidence, it is more likely than not that such benefits will not be realized. As of December 31, 2014, the Company has a net operating loss carryforward for federal and state income tax purposes of approximately $24,000. The net operating loss carryforward will begin to expire in 2029.
	The benefit from income taxes differs from the amount computed by applying the United States (US) federal income tax rate of thirty-four percent (34%) in 2014 and 2013 to loss before income taxes for the years ended December 31, 2014 and 2013 as follows:
		Year Ended			Year Ended
		December 31,			December 31,
		2014			2013
	US federal income tax benefit at statutory rate	$	(10,400	)	$	(9,700	)
	Other		(100	)		—
	Change in valuation allowance		10,500			9,700
	Benefit from income taxes	$	—		$	—

Subsequent_Event

Subsequent Event	12 Months Ended
	Dec. 31, 2014
Subsequent Event	13. Subsequent Events
	The Company evaluated all events or transactions that occurred after the balance sheet date of December 31, 2014 through March 12, 2015.
	Note Purchase Agreement
	On January 12, 2015, the Company entered into a Note Purchase Agreement and Convertible Promissory Note with various persons and entities named within the agreement (“the Holders”) under which the Holders provided a $3,000,000 loan in the form of a convertible promissory note (“the Note”) to be used solely to fund the operations of the Company. The Note contains interest computed at a rate of 8%, compounded annually, with a maturity date of the earliest to occur of: (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default. Interest is due and payable on the maturity date. Prepayment of principal or interest is not allowed on the Note without the prior written consent of the holders. The Note is mandatorily convertible into such class of stock of the Company issued upon the completion of a qualified initial public offering or qualified financing, as defined in the agreement, in an amount equal to the total unpaid principal and interest divided by the price per share offered to the public in the qualified IPO or the price per share of the equity securities paid by other investors in a qualified financing.
	Convertible Promissory Note
	On January 20, 2015, in accordance with the Janssen license agreement described in Note 7, the Company entered into a Convertible Promissory Note with JJDC for $1,000,000. The note contains interest computed at a rate of 8% with a maturity date of the earliest to occur of: (i) May 31, 2016, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default. Interest is due and payable on the maturity date, with prepayment of principal or interest not allowed. The note will automatically convert into such class of shares of the Company issued upon the completion of a qualified equity financing at the lowest per share price offered in the round.
	February 2015 Note Purchase Agreement
	On February 11, 2015, the Company entered into a Note Purchase Agreement and Convertible Promissory Notes with entities named within the agreement (“the February 2015 Note Holders”) under which the February 2015 Note Holders provided totaling $1,000,000 loan in the form of convertible promissory notes. These Convertible Promissory Notes contain interest computed at a rate of 8%, compounded annually, with a maturity date of the earliest to occur of: (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default. Interest is due and payable on the maturity date. Prepayment of principal or interest is not allowed on the note without the prior written consent of the holders. The notes will automatically convert into such class of stock of the Company issued upon the completion of a qualified initial public offering or qualified financing, as defined in the agreement, in an amount equal to the total unpaid principal and interest divided by the price per share offered to the public in the qualified IPO or the price per share of the equity securities paid by other investors in a qualified financing.
	Sponsored Research Agreement
	On February 15, 2015, the Company entered into a Sponsored Research Agreement with Michigan under which the Company will sponsor up to $2,725,000 of research at Michigan over a three-year period. The Company will receive an non-exclusive right to any technology developed under the agreement and has an option right for an exclusive right to any such licenses developed under the agreement. The Sponsored Research Agreement allows for termination with notice at any time by the Company. In the event of termination by the Company prior to the second anniversary of the agreement, other than due to breach by Michigan, the Company will be required to pay costs budgeted through the second anniversary up to $2,000,000 of the sponsored research amount. Any costs incurred for the Sponsored Research Agreement will be expensed as incurred.
	Michigan Amended License Agreement
	On March 3, 2015, the Company and Michigan entered into an amendment to the Michigan license agreement which redefined a qualified financing as the first sale of the Company’s capital stock in which the Company receives certain gross proceeds from the financing. The sale of the Company’s common stock on March 6, 2015 as described below was a qualified financing.
	Merger and Private Financing
	On March 6, 2015, the Company, Zeta Acquisition Corp. III, a public shell company (“Zeta”), and Kura Operations, Inc., a wholly-owned subsidiary of Zeta (“Merger Sub”), entered into an Agreement and Plan of Merger dated March 6, 2015 (the “Merger Agreement”). Pursuant to the Merger Agreement, Merger Sub merged with and into the Company, with the Company remaining as the surviving entity and a wholly-owned operating subsidiary of Zeta (the “Merger”). At the effective time of the Merger (the “Effective Time”), the name of the Company was changed to Kura Operations, Inc. Immediately following the Effective Time, a newly organized wholly-owned subsidiary of Zeta named “Kura Oncology, Inc.” merged with and into Zeta, with the surviving entity named Kura Oncology, Inc. (“Parent”).
	Pursuant to the terms of the Merger Agreement, at the Effective Time, each share of common stock of the Company outstanding immediately prior to the Effective Time was exchanged for one-half (0.5) of a share of common stock of Parent. Parent issued an aggregate of 14,508,177 shares of common stock upon such exchange of the issued shares of the Company common stock. In addition, at the Effective Time, Parent assumed the Company’s 2014 Plan. As of the Effective Time, there were no outstanding options to purchase shares of the Company common stock under the 2014 Plan.
	Immediately prior to the Merger, on March 6, 2015, the Company sold to investors 16,561,396 shares of its common stock at a price of $3.16 per share for gross proceeds of $52,334,011 (the “New Money Financing”). The New Money Financing represented a qualified financing conversion event pursuant to the outstanding convertible promissory notes. As such, upon closing the New Money Financing, $7,500,000 in principal and $114,849 in accrued interest through February 28, 2015 automatically converted into 2,409,740 shares of the Company’s common stock.
	The Company is considered the accounting acquirer in the Merger and will account for the transaction as a capital transaction because the Company’s stockholders received 100% of the voting rights in the combined entity and the Company’s senior management represents all of the senior management of the combined entity.
Zeta Acquisition Corp III
Subsequent Event	7. Subsequent Event
	Subsequent to year end, a stockholder advanced the Company $15,000. The note bears interest at 6% and is due on demand.

Nature_of_Operations_and_Signi

Nature of Operations and Significant Accounting Policies (Zeta Acquisition Corp III)	12 Months Ended
	Dec. 31, 2014
Zeta Acquisition Corp III
Nature of Operations and Significant Accounting Policies	1. Nature of Operations and Significant Accounting Policies
	Nature of Operations
	Zeta Acquisition Corp. III (the “Company”) was incorporated under the laws of the State of Delaware on November 16, 2007. The Company is a new enterprise in the development stage as defined by Accounting Standards Codification (“ASC”) Topic 915, Development Stage Entities. The Company was organized as a vehicle to investigate and, if such investigation warrants, acquire a target company or business seeking the perceived advantages of being a publicly held corporation. The Company’s principal business objective for the next twelve (12) months and beyond will be to achieve long-term growth potential through a combination with a business. The Company will not restrict its potential candidate target companies to any specific business, industry or geographical location and, thus, may acquire any type of business.
	Liquidity
	Since its inception, the Company has generated no revenues and has incurred a net loss of $204,691. Since inception, the Company has been dependent upon the receipt of capital investment or other financing to fund its continuing activities. The Company has not identified any business combination and therefore, cannot ascertain with any degree of certainty the capital requirements for any particular transaction. In addition, the Company is dependent upon certain related parties to provide continued funding and capital resources. During 2014, the Company received loans of $15,000 to fund operations (Note 2). The accompanying financial statements have been presented on the basis of the continuation of the Company as a going concern and do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from those estimates.
	Cash and Cash Equivalents
	For purposes of the statement of cash flows, the Company considers all highly liquid investments with a maturity of three (3) months or less to be cash equivalents.
	Income Taxes
	The Company accounts for income taxes in accordance with ASC Topic 740, Income Taxes, which requires the recognition of deferred tax liabilities and assets at currently enacted tax rates for the expected future tax consequences of events that have been included in the financial statements or tax returns. A valuation allowance is recognized to reduce the net deferred tax asset to an amount that is more likely than not to be realized.
	Fair Value of Financial Instruments
	Pursuant to ASC Topic 820-10, Fair Value Measurements and Disclosures, the Company is required to estimate the fair value of all financial instruments included on its balance sheet as of December 31, 2014 and 2013. The Company considers the carrying value of cash and cash equivalents, accounts payable, accrued expenses, accrued interest, and notes payable to stockholders to approximate fair value due to their short maturities.
	Net Loss Per Share
	Basic loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. The Company currently has no dilutive securities and as such, basic and diluted loss per share are the same for all periods presented.
	Recently Issued Accounting Pronouncements
	In June 2014, the Financial Accounting Standards Board, (“FASB”), issued Accounting Standards Update, (“ASU”), No. 2014-10, which eliminates the concept of a development stage entity, (“DSE”), in its entirety from United States Generally Accepted Accounting Principles, (“U.S. GAAP”). Under existing guidance, DSE’s are required to report incremental information, including inception-to-date financial information, in their financial statements. A DSE is an entity devoting substantially all of its efforts to establishing a new business and for which either planned principal operations have not yet commenced or have commenced but there has been no significant revenues generated from that business. Entities classified as DSE’s will no longer be subject to these incremental reporting requirements after adopting ASU No. 2014-10. ASU No. 2014-10 is effective for fiscal years beginning after December 15, 2014, with early adoption permitted. Retrospective application is required for the elimination of incremental DSE disclosures. At this time the Company has not elected early adoption of ASU No. 2014-10.

Preferred_Stock

Preferred Stock (Zeta Acquisition Corp III)	12 Months Ended
	Dec. 31, 2014
Zeta Acquisition Corp III
Preferred Stock	3. Preferred Stock
	The Company is authorized to issue 10,000,000 shares of preferred stock with such designations, voting and other rights and preferences as may be determined from time to time by the Board of Directors.

Common_Stock

Common Stock (Zeta Acquisition Corp III)	12 Months Ended
	Dec. 31, 2014
Zeta Acquisition Corp III
Common Stock	4. Common Stock
	The Company is authorized to issue 100,000,000 shares of common stock with such designations, voting and other rights and preferences as may be determined from time to time by the Board of Directors. During December 2007, the Company issued 5,000,000 shares of its common stock pursuant to a private placement for $50,000.

Commitment

Commitment (Zeta Acquisition Corp III)	12 Months Ended
	Dec. 31, 2014
Zeta Acquisition Corp III
Commitment	6. Commitment
	The Company utilizes the office space and equipment of an officer and director at no cost on a month-to-month basis. Management estimates such amounts to be di minimis.

Nature_of_Operations_and_Signi1

Nature of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Use of Estimates	Use of Estimates
	The Company’s financial statements are prepared in accordance with accounting principles generally accepted in the United States (“GAAP”). The preparation of the Company’s financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period.
	Reported amounts and note disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. All revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.
Concentration of Credit Risk	Concentration of Credit Risk
	Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits and limits its exposure to cash risk by placing its cash with credit quality rating financial institutions.
Property and Equipment	Property and Equipment
	Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets which is three years for each asset class.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
	The Company reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. If such circumstances are determined to exist, an estimate of undiscounted future cash flows produced by the long-lived asset, including its eventual residual value, is compared to the carrying value to determine whether impairment exists. In the event that such cash flows are not expected to be sufficient to recover the carrying amount of the assets, the assets are written-down to their estimated fair values. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, the Company believes that future cash flows to be received support the carrying value of its long-lived assets and, accordingly, has not recognized any impairment losses through December 31, 2014.
Convertible Notes and Derivative Accounting	Convertible Notes and Derivative Accounting
	At inception, the Company performs an assessment of all embedded features of a debt instrument to determine if (1) such features should be bifurcated and separately accounted for, and (2) if bifurcation requirements are met, whether such features should be classified and accounted for as equity or liability. The fair value of the embedded feature is measured initially, included as a liability on the balance sheet, and remeasured each reporting period. Any changes in fair value are recorded in the statement of operations. The Company monitors, on an ongoing basis, whether events or circumstances could give rise to a change in its classification of embedded features.
	The Company accounts for its convertible notes, that may be settled in cash upon conversion (including partial cash settlement), by separating the liability and equity components of the instruments in a manner that reflects the Company’s nonconvertible debt borrowing rate. The Company determines the carrying amount of the liability component by measuring the fair value of similar debt instruments that do not have the conversion feature. If a similar debt instrument does not exist, the Company estimates the fair value by using assumptions that market participants would use in pricing a debt instrument, including market interest rates, credit standing, yield curves and volatilities. Determining the fair value of the debt component requires the use of accounting estimates and assumptions. These estimates and assumptions are judgmental in nature and could have a significant impact on the determination of the debt component and the associated non-cash interest expense.
Deferred Rent	Deferred Rent
	Deferred rent consists of the difference between cash payments and the recognition of rent expense on a straight-line basis for the facilities the Company occupies. The Company’s lease for its facilities provides for fixed increases in minimum annual rental payments. The total amount of rental payments due over the lease term is being charged to rent expense ratably over the life of the lease. The Company’s deferred rent balance is contained within other long-term liabilities on the Company’s Balance Sheet.
Research and Development Costs	Research and Development Costs
	Research and development costs are expensed as incurred. Research and development costs consist of direct and indirect internal costs related to specific projects as well as fees paid to other entities that conduct certain research activities on the Company’s behalf. Payments that the Company makes in connection with in-licensed technology for a particular research and development project that have no alternative future uses (in other research and development projects or otherwise) and therefore no separate economic values are expensed as research and development costs at the time such costs are incurred. As of December 31, 2014, the Company has no in-licensed technologies that have alternative future uses in research and development projects or otherwise.
Patent Costs	Patent Costs
	The Company expenses all costs as incurred in connection with patent applications, including direct application fees, and the legal and consulting expenses related to making such applications, and such costs are included in general and administrative expenses within the Company’s Statement of Operations and Comprehensive Loss.
Share-Based Compensation	Share-Based Compensation
	Restricted stock awards are valued based on the fair value on the grant date. The fair value of restricted stock awards expected to vest are recognized and amortized on a straight-line basis over the requisite service period of the award, which is generally four years. Restricted stock awards granted to non-employees are recorded at their fair value on the earlier of the performance commitment date or the date the services required are completed and are marked to market during the service period. Non-employee restricted stock awards are remeasured and expensed as they vest based on the intrinsic value method.
	The Company’s equity incentive plan allows for the issuance of restricted stock awards to employees and non-employee consultants that may be subject to vesting. The unvested shares of any restricted stock awards are held in escrow as the stock award vests or until award holder termination, whichever occurs first. In the event of a termination, the Company has the right of repurchase, at its option, for the portion of unvested stock awards from the terminated award holder. The repurchase price for unvested stock awards will be the lower of (i) the fair market value of the shares of common stock on the date of repurchase or (ii) their original purchase price. For all unvested stock awards, a liability is established related to the cash received for the unvested portion of the stock award, which represents the Company’s obligation if all award holders were to be terminated, and is recorded within other long-term liabilities on the Company’s Balance Sheet.
Income Taxes	Income Taxes
	Income taxes have been accounted for using the asset and liability method. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates applicable to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance against deferred tax assets is recorded if, based upon the weight of all available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. For uncertain tax positions that meet “a more likely than not” threshold, the Company recognizes the benefit of uncertain tax positions in the financial statements.
Comprehensive Loss	Comprehensive Loss
	The Company is required to report all components of comprehensive loss, including net loss, in the financial statements in the period in which they are recognized. Comprehensive loss is defined as the change in equity during a period from transactions and other events and circumstances from non-owner sources, including unrealized losses on investments. Net loss and comprehensive loss were the same for the period presented, therefore, a separate statement of comprehensive loss is not included in the accompanying financial statements.
Segment Reporting	Segment Reporting
	Operating segments are components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker for purposes of making decisions regarding resource allocation and assessing performance. To date, the Company has viewed its operations and managed its business as one segment operating primarily in the United States.
Fair Value Measurements	Fair Value Measurements
	The Company categorizes its assets and liabilities measured at fair value in accordance with the authoritative accounting guidance that establishes a consistent framework for measuring fair value, and expands disclosures for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as the exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, 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.
	At December 31, 2014, the Company did not have financial assets that are measured at fair value on a recurring basis. The carrying amounts of the Company’s financial instruments, which include cash, prepaid expenses, accounts payable, accrued expenses and all related party amounts approximate their fair values at December 31, 2014, primarily due to their short-term nature. The Company believes the fair value of its convertible notes approximates their carrying value as of December 31, 2014. No transfers between levels have occurred during the periods presented. Liabilities measured at fair value on a recurring basis as of December 31, 2014 are as follows:
					Fair Value Measurements at December 31, 2014
			Balance as of		Quoted Prices		Significant		Significant
			December 31,		in Active		Other		Unobservable
			2014		Markets for		Observable		Inputs
					Identical Assets		Inputs		(Level 3)
					(Level 1)		(Level 2)
	Liabilities
	Embedded derivative liability (1)		$	196,000	$	—	$	—	$	196,000
	-1	The Company’s license agreement with the with The Regents of the University of California San Francisco (“UCSF”), further described in Note 7, provides for an indexed milestone payment upon the occurrence of a qualified preferred stock financing and a subsequent initial public offering or a change of control event, as defined in the agreement. The indexed milestone was determined to qualify as an embedded derivative liability requiring an estimate of fair value.
	The Company estimates the fair value of its derivative liabilities at the time of issuance and subsequent remeasurement at each reporting date using a probability model that considers the probability of achieving the events that would trigger such liabilities and the estimated time period the liabilities would be outstanding. The estimates are based, in part, on subjective assumptions and could differ materially in the future. Changes to these assumptions can have a significant impact on the fair value of the derivative liabilities.
	The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs:
			Derivative
			Liabilities
	Balance at August 22, 2014 (Inception)		$	—
	Issuance of derivative liability (1)			196,000
	Change in fair value (2)			—
	Balance at December 31, 2014		$	196,000
	-1	The amount is included within research and development expenses on the Company’s Statement of Operations and Comprehensive Loss.
	-2	The license agreement was executed in November 2014 and no change in the valuation occurred between the execution date and December 31, 2014.
Net Loss Per Share	Net Loss per Share
	Basic net loss per 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 under the Company’s equity plan. 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.
	Potentially dilutive securities, which includes unvested stock awards of 9,065,748 are excluded from the calculation of diluted net loss per share due to the anti-dilutive effect of the securities. In addition, the Company has $2,500,000 in principal of outstanding convertible promissory notes, issued in October and December 2014, that are convertible into common stock upon the occurrence of various future events at prices that are not determinable until the occurrence of those future events. As such, the Company has excluded these convertible notes payable from the calculation of diluted net loss per share.
Zeta Acquisition Corp III
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting periods. Actual results could differ from those estimates.
Income Taxes	Income Taxes
	The Company accounts for income taxes in accordance with ASC Topic 740, Income Taxes, which requires the recognition of deferred tax liabilities and assets at currently enacted tax rates for the expected future tax consequences of events that have been included in the financial statements or tax returns. A valuation allowance is recognized to reduce the net deferred tax asset to an amount that is more likely than not to be realized.
Net Loss Per Share	Net Loss Per Share
	Basic loss per share is computed by dividing net loss by the weighted-average number of common shares outstanding for the period. The Company currently has no dilutive securities and as such, basic and diluted loss per share are the same for all periods presented.
Liquidity	Liquidity
	Since its inception, the Company has generated no revenues and has incurred a net loss of $204,691. Since inception, the Company has been dependent upon the receipt of capital investment or other financing to fund its continuing activities. The Company has not identified any business combination and therefore, cannot ascertain with any degree of certainty the capital requirements for any particular transaction. In addition, the Company is dependent upon certain related parties to provide continued funding and capital resources. During 2014, the Company received loans of $15,000 to fund operations (Note 2). The accompanying financial statements have been presented on the basis of the continuation of the Company as a going concern and do not include any adjustments relating to the recoverability and classification of recorded asset amounts or the amounts and classification of liabilities that might be necessary should the Company be unable to continue as a going concern.
Cash and Cash Equivalents	Cash and Cash Equivalents
	For purposes of the statement of cash flows, the Company considers all highly liquid investments with a maturity of three (3) months or less to be cash equivalents.
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	Pursuant to ASC Topic 820-10, Fair Value Measurements and Disclosures, the Company is required to estimate the fair value of all financial instruments included on its balance sheet as of December 31, 2014 and 2013. The Company considers the carrying value of cash and cash equivalents, accounts payable, accrued expenses, accrued interest, and notes payable to stockholders to approximate fair value due to their short maturities.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements
	In June 2014, the Financial Accounting Standards Board, (“FASB”), issued Accounting Standards Update, (“ASU”), No. 2014-10, which eliminates the concept of a development stage entity, (“DSE”), in its entirety from United States Generally Accepted Accounting Principles, (“U.S. GAAP”). Under existing guidance, DSE’s are required to report incremental information, including inception-to-date financial information, in their financial statements. A DSE is an entity devoting substantially all of its efforts to establishing a new business and for which either planned principal operations have not yet commenced or have commenced but there has been no significant revenues generated from that business. Entities classified as DSE’s will no longer be subject to these incremental reporting requirements after adopting ASU No. 2014-10. ASU No. 2014-10 is effective for fiscal years beginning after December 15, 2014, with early adoption permitted. Retrospective application is required for the elimination of incremental DSE disclosures. At this time the Company has not elected early adoption of ASU No. 2014-10.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Liabilities Measured at Fair Value on Recurring Basis	Liabilities measured at fair value on a recurring basis as of December 31, 2014 are as follows:
					Fair Value Measurements at December 31, 2014
			Balance as of		Quoted Prices		Significant		Significant
			December 31,		in Active		Other		Unobservable
			2014		Markets for		Observable		Inputs
					Identical Assets		Inputs		(Level 3)
					(Level 1)		(Level 2)
	Liabilities
	Embedded derivative liability (1)		$	196,000	$	—	$	—	$	196,000
	-1	The Company’s license agreement with the with The Regents of the University of California San Francisco (“UCSF”), further described in Note 7, provides for an indexed milestone payment upon the occurrence of a qualified preferred stock financing and a subsequent initial public offering or a change of control event, as defined in the agreement. The indexed milestone was determined to qualify as an embedded derivative liability requiring an estimate of fair value.
Fair Value, Inputs, Level 3 [Member]
Liabilities Measured at Fair Value on Recurring Basis	The following table provides a reconciliation of all liabilities measured at fair value using Level 3 significant unobservable inputs:
			Derivative
			Liabilities
	Balance at August 22, 2014 (Inception)		$	—
	Issuance of derivative liability (1)			196,000
	Change in fair value (2)			—
	Balance at December 31, 2014		$	196,000
	-1	The amount is included within research and development expenses on the Company’s Statement of Operations and Comprehensive Loss.
	-2	The license agreement was executed in November 2014 and no change in the valuation occurred between the execution date and December 31, 2014.

Property_and_equipment_net_Tab

Property and equipment, net (Tables)	12 Months Ended
	Dec. 31, 2014
Property and Equipment	Property and equipment consisted of the following:
		December 31,
		2014
	Computer equipment	$	25,862
	Software		2,250
			28,112
	Less: accumulated depreciation		(1,466	)
	Property and equipment, net	$	26,646

Accounts_payable_and_accrued_l1

Accounts payable and accrued liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Accounts Payable and Accrued Liabilities	Accounts payable and accrued liabilities consisted of the following:
		December 31,
		2014
	Accounts payable	$	225,642
	Accrued expenses		567,887
	Accrued compensation and benefits		39,404
	Total accounts payable and accrued expenses	$	832,933

Notes_Payable_Tables

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2014
Notes Payable and Unamortized Discount	Total notes payable and unamortized discount balances are as follows:
		December 31,
		2014
	Face value of convertible notes	$	2,500,000
	Accrued interest		36,483
	Debt issuance costs associated with fair value of derivative		(7,500	)
	Total	$	2,528,983
	Less: current portion		(2,035,565	)
	Total convertible notes, long-term	$	493,418

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Future Minimum Payments Required under Leases	Future minimum payments required under the leases as of December 31, 2014 are summarized as follows:
	Year Ending December 31,
	2015	$	111,062
	2016		87,573
	Total minimum lease payments	$	198,635

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
Summary of Restricted Share Activity	The following is a summary of restricted share activity:
		Number of			Weighted
		Shares			Average
					Grant Date
					Fair Value
	Balance at August 22, 2014 (Inception)		—		$	—
	Granted		9,887,000		$	0.001
	Vested		(821,252	)
	Unvested at December 31, 2014		9,065,748		$	0.001
	Vested at December 31, 2014		821,252		$	0.001

Income_Tax_Disclosure_Tables

Income Tax Disclosure (Tables)	12 Months Ended
	Dec. 31, 2014
Schedule of Effective Income Tax Rate Reconciliation	The Company’s effective income tax differs from the statutory federal rate of 34% at December 31, 2014 due to the following:
		Period from
		August 22, 2014
		(Inception) to
		December 31,
		2014
	Benefit for income taxes at statutory federal rate	$	(1,248,230	)
	State income tax (benefit), net of federal benefit		(224,752	)
	Share-based compensation		80,450
	Research and development tax credits		(28,288	)
	Other		13,307
	Valuation allowance		1,407,513
	Income tax expense	$	—
Components Of Deferred Tax Assets	Significant components of the Company’s deferred tax assets at December 31, 2014 are shown below:
		December 31, 2014
	Deferred tax assets
	Intangibles	$	731,622
	Net operating loss carryforwards		441,622
	Research and development tax credit carryforwards		28,288
	Accruals		204,608
	Other		1,373
	Total deferred tax assets		1,407,513
	Less valuation allowance		(1,407,513	)
	Net deferred tax assets	$	—
Zeta Acquisition Corp III
Schedule of Effective Income Tax Rate Reconciliation	The benefit from income taxes differs from the amount computed by applying the United States (US) federal income tax rate of thirty-four percent (34%) in 2014 and 2013 to loss before income taxes for the years ended December 31, 2014 and 2013 as follows:
		Year Ended			Year Ended
		December 31,			December 31,
		2014			2013
	US federal income tax benefit at statutory rate	$	(10,400	)	$	(9,700	)
	Other		(100	)		—
	Change in valuation allowance		10,500			9,700
	Benefit from income taxes	$	—		$	—
Components Of Deferred Tax Assets	The tax effects of temporary differences that give rise to significant portions of the Company’s net deferred tax asset at December 31, 2014 and 2013 are as follows:
		December 31,			December 31,
		2014			2013
	Deferred tax asset:
	Capitalized formation costs	$	61,400		$	53,300
	Net operating loss carryforward		8,200			5,800
	Valuation allowance		(69,600	)		(59,100	)
	Net deferred tax asset recognized	$	—		$	—

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation - Additional Information (Detail) (USD $)	Dec. 31, 2014
Organization And Basis Of Presentation [Line Items]
Accumulated deficit	($3,671,266)

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	4 Months Ended
	Dec. 31, 2014
	Segment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment, estimated useful life	3 years
Impairment losses on long-lived assets	$0
Number of operating segment	1
Restricted Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock awards, vesting period	4 years
Equity Option [Member]
Summary Of Significant Accounting Policies [Line Items]
Potentially dilutive securities, excluded from the calculation of diluted net loss per share due to the anti-dilutive effect of the securities	9,065,748
Convertible Debt Securities [Member]
Summary Of Significant Accounting Policies [Line Items]
Principal of outstanding convertible promissory notes	$2,500,000

Liabilities_Measured_at_Fair_V

Liabilities Measured at Fair Value on Recurring Basis (Detail) (Embedded derivative liability [Member], USD $)	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	$196,000	[1]
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	0	[1]
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	0	[1]
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities	$196,000	[1]
[1]	The Company's license agreement with the with The Regents of the University of California San Francisco ("UCSF"), further described in Note 7, provides for an indexed milestone payment upon the occurrence of a qualified preferred stock financing and a subsequent initial public offering or a change of control event, as defined in the agreement. The indexed milestone was determined to qualify as an embedded derivative liability requiring an estimate of fair value.

Reconciliation_of_All_Liabilit

Reconciliation of All Liabilities Measured as Fair Value Using Level 3 Significant Unobservable Input (Detail) (USD $)	4 Months Ended
	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Beginning balance	$0
Issuance of derivative liability	196,000	[1]
Change in fair value	0	[2]
Ending balance	$196,000
[1]	The amount is included within research and development expenses on the Company's Statement of Operations and Comprehensive Loss.
[2]	The license agreement was executed in November 2014 and no change in the valuation occurred between the execution date and December 31, 2014.

Property_and_Equipment_Detail

Property and Equipment (Detail) (USD $)	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$28,112
Less: accumulated depreciation	-1,466
Property and equipment, net	26,646
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	25,862
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$2,250

Recovered_Sheet1

Accounts Payable and Accrued Liabilities (Detail) (USD $)	Dec. 31, 2014
Accounts Payable And Accrued Expenses [Line Items]
Accounts payable	$225,642
Accrued expenses	567,887
Accrued compensation and benefits	39,404
Total accounts payable and accrued expenses	$832,933

Notes_Payable_Additional_Infor

Notes Payable - Additional Information (Detail) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Oct. 08, 2014	Dec. 23, 2014
Notes Payable, Stockholders (Textual)
Convertible notes payable, related party, current	2,035,565
Convertible notes payable, related party, non current	493,418
Note Purchase Agreement and Convertible Promissory Note
Notes Payable, Stockholders (Textual)
Debt instrument maturity date, description	The earliest to occur of (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
Araxes Pharma LLC | Note Purchase Agreement and Convertible Promissory Note | Convertible Debt Securities [Member]
Notes Payable, Stockholders (Textual)
Convertible notes payable, related party, current		2,000,000
Interest rate		8.00%
Debt instrument maturity date, description		The earliest to occur of (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
Araxes Pharma LLC | Asset Purchase Agreement [Member] | Convertible Debt Securities [Member]
Notes Payable, Stockholders (Textual)
Interest rate			8.00%
Debt instrument maturity date, description			The earliest to occur (i) of May 31, 2016 (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
Convertible notes payable, related party, non current			$500,000

Notes_Payable_and_Unamortized_

Notes Payable and Unamortized Discount (Detail) (USD $)	Dec. 31, 2014
Notes Payable, Stockholders (Textual)
Face value of convertible notes	$2,500,000
Accrued interest	36,483
Debt issuance costs associated with fair value of derivative	-7,500
Total	2,528,983
Less: current portion	-2,035,565
Total convertible notes, long-term	493,418
Total	$2,528,983

License_and_Asset_Purchase_Agr1

License and Asset Purchase Agreements - Additional Information (Detail) (USD $)	0 Months Ended	4 Months Ended
	Dec. 18, 2014	Dec. 31, 2014	Dec. 23, 2014
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Convertible notes payable, related party, non current		$493,418
Janssen License Agreement | Up-front Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceed from license agreement	1,000,000
University of San Francisco License Agreement | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received		81,675,000
University of San Francisco License Agreement | Maximum | Development activities
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received		1,175,000
University of San Francisco License Agreement | Maximum | Regulatory
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received		30,500,000
University of San Francisco License Agreement | Maximum | Product Sales
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received		50,000,000
University of San Francisco License Agreement | Up-front Payment Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Proceed from license agreement		1,075,000
Asset Purchase Agreement [Member] | Araxes Pharma LLC
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received			9,650,000
Asset Purchase Agreement [Member] | Araxes Pharma LLC | Convertible Debt Securities [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Convertible notes payable, related party, non current			500,000
Asset Purchase Agreement [Member] | Araxes Pharma LLC | Development activities
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received			1,150,000
Asset Purchase Agreement [Member] | Araxes Pharma LLC | Regulatory
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payment to be received			$8,500,000

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	4 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Oct. 06, 2014	Dec. 31, 2014	Aug. 29, 2014
Loss Contingencies [Line Items]
Rent expense	$27,249
Commitment to provide charitable contribution	285,000		285,000
Commitment to provide charitable contribution, description	The Company is obligated to make a charitable gift of $285,000 to the Leukemia and Lymphoma Society in connection with the Michigan agreement described in Note 7 to be paid in three equal parts the first part due in January 2015, the second part due in January 2016 and the final part due in January 2017. The full amount of the charitable gift has been accrued as of December 31, 2014.
MASSACHUSETTS | Monthly
Loss Contingencies [Line Items]
Rent expense		4,785
Araxes Pharma LLC
Loss Contingencies [Line Items]
Rent expense	14,906
Percentage of rent escalation				3.00%
Sublease expiration date			30-Aug-16
Araxes Pharma LLC | Monthly
Loss Contingencies [Line Items]
Rent expense			4,820	$4,680

Future_Minimum_Payments_Requir

Future Minimum Payments Required under Leases (Detail) (USD $)	Dec. 31, 2014
Property Subject to or Available for Operating Lease [Line Items]
2015	$111,062
2016	87,573
Total minimum lease payments	$198,635

Stockholders_Equity_Details_Te

Stockholders' Equity (Details Textual) (Detail) (USD $)	4 Months Ended
	Dec. 31, 2014	Aug. 31, 2014
Class of Stock [Line Items]
Common shares reserved for future issuance pursuant to future option grants	1,113,000
Convertible promissory notes outstanding	$2,528,983
Liability associated with shares issued with repurchase rights	12,786
Shares subject to repurchase	9,065,748
Share-based compensation expense related to non-employees	236,618
Restricted Stock [Member]
Class of Stock [Line Items]
Stock awards vesting period	4 years
Share-based compensation expense related to non-employees	236,618
2014 Plan
Class of Stock [Line Items]
Shares reserved for issuance under the plan		11,000,000
Term of options to be granted under the Plan	10 years
Options granted under the plan	0
2014 Plan | Restricted Stock [Member]
Class of Stock [Line Items]
Stock awards vesting period	4 years
2014 Plan | Restricted Stock [Member] | Cliff Vesting period
Class of Stock [Line Items]
Stock awards vesting period	1 year
Convertible Debt Securities [Member]
Class of Stock [Line Items]
Convertible promissory notes outstanding	$2,500,000

Summary_of_Restricted_Share_Ac

Summary of Restricted Share Activity (Detail) (Restricted Stock [Member], USD $)	4 Months Ended
	Dec. 31, 2014
Restricted Stock [Member]
Number of Shares
Granted	9,887,000
Vested	-821,252
Ending Balance	9,065,748
Vested	821,252
Weighted Average Grant Date Fair Value
Granted	$0.00
Ending Balance	$0.00
Vested at December 31, 2014	$0.00

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (USD $)	4 Months Ended	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Aug. 29, 2014	Oct. 08, 2014	Dec. 23, 2014
Related Party Transaction [Line Items]
Convertible notes payable, related party, current	$2,035,565	$2,035,565
Convertible notes payable, related party, non current	493,418	493,418
Rent expense	27,249
Araxes Pharma LLC
Related Party Transaction [Line Items]
Rent expense	14,906
Sublease expiration date		30-Aug-16
Management service agreement, fixed		100,000
Management service agreement, full time equivalents performing collaboration services		350,000
Management Fee, Description		The Company has a management services agreement with Araxes under which Araxes pays the Company a fixed $100,000 a month for management services. In addition, the agreement allows for Araxes to pay the Company an amount equal to the number of full time equivalents (bFTEb) performing collaboration services for Araxes, at an FTE rate of $350,000, plus actual expenses as reasonably incurred. The agreement has an initial term expiring on December 31, 2015 and 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 December 31, 2015 or the expiration of the then-renewal term.
Research and development services expense at full time equivalents rate		400,000
Araxes Pharma LLC | Monthly
Related Party Transaction [Line Items]
Rent expense		4,820	4,680
Araxes Pharma LLC | Note Purchase Agreement and Convertible Promissory Note | Convertible Debt Securities [Member]
Related Party Transaction [Line Items]
Convertible notes payable, related party, current				2,000,000
Araxes Pharma LLC | Asset Purchase Agreement [Member] | Convertible Debt Securities [Member]
Related Party Transaction [Line Items]
Convertible notes payable, related party, non current					$500,000

Income_Taxes_Details_Textual_D

Income Taxes (Details Textual) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
IncomeTaxesTextualAbstract
Effective federal statutory income tax rate, Percent	34.00%
Loss carryforwards begin to expire	2034
Valuation allowance	$1,407,513
Income tax examination, likelihood of unfavorable settlement	An uncertain tax position will not be recognized if it has less than a 50% likelihood of being sustained.
Unrecognized tax benefits	0
Unrecognized interest or penalties	0
Zeta Acquisition Corp III
IncomeTaxesTextualAbstract
Effective federal statutory income tax rate, Percent	34.00%	34.00%
Net operating loss	24,000
Loss carryforwards begin to expire	2029
Valuation allowance	69,600	59,100
Domestic Tax Authority
IncomeTaxesTextualAbstract
Net operating loss	1,087,279
Research credit carryforwards	17,919
Credit carry forward begin to expire	2034
State and Local Jurisdiction
IncomeTaxesTextualAbstract
Net operating loss	1,248,532
Research credit carryforwards	$15,710
Credit carry forward begin to expire	2029

Benefit_from_Income_Tax_Detail

Benefit from Income Tax (Detail) (USD $)	4 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Reconciliation Of Effective Income Tax Rate [Line Items]
Benefit for income taxes at statutory federal rate	($1,248,230)
State income tax (benefit), net of federal benefit	-224,752
Share-based compensation	80,450
Research and development tax credits	-28,288
Other	13,307
Change in valuation allowance	1,407,513
Benefit from income taxes	0
Zeta Acquisition Corp III
Reconciliation Of Effective Income Tax Rate [Line Items]
Benefit for income taxes at statutory federal rate		-10,400	-9,700
Other		-100
Change in valuation allowance		10,500	9,700
Benefit from income taxes		$0	$0

Income_Taxes_Detail

Income Taxes (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deferred tax asset:
Intangibles	$731,622
Net operating loss carryforward	441,622
Research and development tax credit carryforwards	28,288
Accruals	204,608
Other	1,373
Total deferred tax assets	1,407,513
Less valuation allowance	-1,407,513
Net deferred tax assets	0
Zeta Acquisition Corp III
Deferred tax asset:
Capitalized formation costs	61,400	53,300
Net operating loss carryforward	8,200	5,800
Less valuation allowance	-69,600	-59,100
Net deferred tax asset recognized	$0	$0

Subsequent_Event_Detail

Subsequent Event (Detail) (USD $)	12 Months Ended	0 Months Ended		85 Months Ended
	Dec. 31, 2014	Feb. 15, 2015	Mar. 06, 2015	Dec. 31, 2014	Jan. 12, 2015	Jan. 20, 2015	Feb. 11, 2015
Merger and Private Financing
Subsequent Event [Line Items]
Business acquisition, voting rights percentage acquired	100.00%			100.00%
Note Purchase Agreement and Convertible Promissory Note
Subsequent Event [Line Items]
Convertible promissory note, maturity date description	The earliest to occur of (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
Janssen License Agreement | Convertible Debt Securities [Member]
Subsequent Event [Line Items]
Convertible promissory note, maturity date description	The earliest to occur of (i) May 31, 2016, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
February 2015 Note Holders
Subsequent Event [Line Items]
Convertible promissory note, maturity date description	The earliest to occur of (i) December 31, 2015, (ii) upon a change in control, as defined in the agreement, or (iii) upon defined events of default.
Subsequent Event | University of Michigan Sponsored Research Agreement [Member]
Subsequent Event [Line Items]
Sponsor of research over three- year		$2,725,000
Sponsored research agreement period		3 years
Sponsored research amount, expensed as incurred		2,000,000
Subsequent Event | Merger and Private Financing
Subsequent Event [Line Items]
Shares sold to investors			16,561,396
Shares sold to investors, share price			$3.16
Sale of stock, gross proceeds			52,334,011
Convertible promissory note, principal amount converted			7,500,000
Accrued interest converted			114,849
Debt instrument conversion, shares issued			2,409,740
Subsequent Event | Merger and Private Financing | Common Stock [Member]
Subsequent Event [Line Items]
Merger agreement, terms			Each share of common stock of the Company outstanding immediately prior to the Effective Time was exchanged for one-half (0.5) of a share of common stock of Parent.
Shares of the Company common stock issued upon exchange pursuant to merger agreement			14,508,177
Subsequent Event | Merger and Private Financing | 2014 Plan
Subsequent Event [Line Items]
Options to purchase shares outstanding			0
Subsequent Event | Note Purchase Agreement and Convertible Promissory Note
Subsequent Event [Line Items]
Convertible promissory note					3,000,000
Convertible promissory note, interest rate					8.00%
Subsequent Event | Janssen License Agreement | Convertible Debt Securities [Member]
Subsequent Event [Line Items]
Convertible promissory note						1,000,000
Convertible promissory note, interest rate						8.00%
Subsequent Event | February 2015 Note Holders
Subsequent Event [Line Items]
Convertible promissory note							1,000,000
Convertible promissory note, interest rate							8.00%
Zeta Acquisition Corp III
Subsequent Event [Line Items]
Sale of stock, gross proceeds				50,000
Stockholder advanced payment	15,000			$15,000
Interest rate	6.00%

Nature_of_Operations_and_Signi2

Nature of Operations and Significant Accounting Policies (Detail) (USD $)	4 Months Ended	12 Months Ended								85 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007	Dec. 31, 2014
Nature Of Operations And Significant Accounting Policies Textual [Abstract]
Net loss	($3,671,266)
Proceeds from related party debt by issuing unsecured promissory note	2,000,000
Zeta Acquisition Corp III
Nature Of Operations And Significant Accounting Policies Textual [Abstract]
Net loss		-30,734	-28,611	-27,315	-27,040	-22,395	-19,996	-33,623	-14,977	-204,691
Proceeds from related party debt by issuing unsecured promissory note		$15,000	$25,000							$135,000

Notes_Payable_Stockholders_Det

Notes Payable, Stockholders (Detail) (Zeta Acquisition Corp III, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2007
Notes Payable, Stockholders (Textual)
Unsecured promissory notes	$15,000	$25,000	$25,000	$35,000	$25,000
Interest rate on unsecured promissory note	6.00%
Accrued interest	24,002	17,175
Stockholder and Officers [Member]
Notes Payable, Stockholders (Textual)
Unsecured promissory notes						$10,000

Preferred_Stock_Detail

Preferred Stock (Detail) (Zeta Acquisition Corp III)	Dec. 31, 2014	Dec. 31, 2013
Zeta Acquisition Corp III
Preferred Stock [Line Items]
Preferred stock, shares authorized	10,000,000	10,000,000

Common_Stock_Detail

Common Stock (Detail) (USD $)	12 Months Ended
	Dec. 31, 2007	Dec. 31, 2014	Dec. 31, 2013
Common Stock (Textual)
Common stock, shares authorized		50,000,000
Zeta Acquisition Corp III
Common Stock (Textual)
Common stock, shares authorized		100,000,000	100,000,000
Common stock issued	5,000,000
Issuance of common stock pursuant to private placement	$50,000