Loxo Oncology (LOXO) 10-Q 14 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	1-May-15
Document and Entity Information
Entity Registrant Name	Loxo Oncology, Inc.
Entity Central Index Key	1581720
Document Type	10-Q
Document Period End Date	31-Mar-15
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		16,687,436
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1

Condensed_Balance_Sheets

Condensed Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$37,255	$43,930
Short-term investments	60,697	62,362
Prepaid expenses with related party	658	663
Other prepaid expenses and current assets	555	821
Total current assets	99,165	107,776
Long-term investments	9,650	6,648
Property and equipment, net	31	12
Security deposit	23	23
Total assets	108,869	114,459
Current liabilities:
Accounts payable	285	239
Accrued expenses and other current liabilities	1,024	1,548
Total liabilities	1,309	1,787
Commitments and contingencies
Stockholders' equity:
Common stock, $0.0001 par value; 125,000,000 shares authorized; 16,644,219 shares issued and 16,634,063 outstanding	2	2
Additional paid-in capital	144,709	143,660
Accumulated deficit	-37,144	-30,962
Accumulated other comprehensive loss	-7	-28
Total stockholders' equity	107,560	112,672
Total liabilities and stockholders' equity	$108,869	$114,459

Condensed_Balance_Sheets_Paren

Condensed Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Condensed Balance Sheets
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issued	16,644,219	16,644,219
Common stock, shares outstanding	16,634,063	16,634,063

Condensed_Statements_of_Operat

Condensed Statements of Operations (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating expenses:
Research and development with related party	$1,918	$1,275
Research and development	1,915	767
General and administrative	2,392	860
Total operating expenses and loss from operations	-6,225	-2,902
Interest income, net	43
Net loss	-6,182	-2,902
Accretion of redeemable convertible preferred stock		-11
Net loss attributable to common stockholders	($6,182)	($2,913)
Per share information:
Net loss per share of common stock, basic and diluted (in dollars per share)	($0.38)	($14.22)
Weighted average shares outstanding, basic and diluted	16,474,269	204,807

Condensed_Statements_of_Compre

Condensed Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income
Net loss	($6,182)	($2,902)
Other comprehensive income:
Unrealized gain on available for sale securities	21
Comprehensive loss	($6,161)	($2,902)

Condensed_Statements_of_Stockh

Condensed Statements of Stockholders' Equity (USD $)	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss	Total
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2014	$2	$143,660	($30,962)	($28)	$112,672
Balance (in shares) at Dec. 31, 2014	16,634,063
Changes Stockholders' Equity
Stock-based compensation expense		1,049			1,049
Other comprehensive income				21	21
Net loss			-6,182		-6,182
Balance at Mar. 31, 2015	$2	$144,709	($37,144)	($7)	$107,560
Balance (in shares) at Mar. 31, 2015	16,634,063

Condensed_Statements_of_Cash_F

Condensed Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities:
Net loss	($6,182)	($2,902)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization of premium and discounts on investments, net	60
Stock-based compensation	1,049	64
Changes in operating assets and liabilities:
Prepaid expenses and other assets	271	-484
Accounts payable	46	22
Accrued expenses	-524	164
Net cash used in operating activities	-5,280	-3,136
Investing activities:
Purchases of available-for-sale securities	-10,275
Proceeds from maturing available-for-sale securities	8,900
Purchase of property, plant and equipment	-20
Net cash used in investing activities	-1,395
Financing activities:
Proceeds from issuance of redeemable convertible preferred stock, net		15,000
Proceeds from the exercise of stock options		75
Net cash provided by financing activities		15,075
Net increase (decrease) in cash and cash equivalents	-6,675	11,939
Cash and cash equivalents-beginning of period	43,930	14,994
Cash and cash equivalents-end of period	37,255	26,933
Supplemental schedule of noncash investing activities:
Unrealized gain on available for sale securities	21
Supplemental schedule of noncash financing activities:
Accretion of redeemable convertible preferred stock		($11)

Organization_and_Description_o

Organization and Description of the Business	3 Months Ended
	Mar. 31, 2015
Organization and Description of the Business
Organization and Description of the Business
	1.Organization and Description of the Business
	Loxo Oncology, Inc. (the “Company”) was incorporated on May 9, 2013 in the State of Delaware.  The Company is committed to the discovery, development, and commercialization of targeted cancer therapies with best-in-class potential.  Loxo Oncology, Inc.’s diverse pipeline reflects the convergence of proven therapeutic technologies with emerging insights into the underlying susceptibilities of cancer and drug resistance.  The Company operates in one segment and has its principal office in Stamford, Connecticut.
	Liquidity
	At March 31, 2015, the Company had working capital of $97.9 million and an accumulated deficit of $37.1 million.  The Company had cash, cash equivalents and investments of $107.6 million at March 31, 2015.  The Company has not generated any product revenues and has not achieved profitable operations.  There is no assurance that profitable operations will ever be achieved, and, if achieved, could be sustained on a continuing basis.  In addition, development activities, clinical and pre-clinical testing, and commercialization of the Company’s products will require significant additional capital.
	The Company believes that its existing cash, cash equivalents, and investments, will be sufficient to enable the Company to continue as a going-concern for a reasonable period of time beyond March 31, 2016.  However, the Company will need to secure additional funding in the future, from one or more equity or debt financings, collaborations, or other sources, in order to carry out all of its planned research and development activities.  If the Company is unable to obtain additional financing or generate license or product revenue, the lack of liquidity could have a material adverse effect on the Company’s future prospects.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies
	2.Summary of Significant Accounting Policies
	Basis of Presentation
	The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).  Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).
	Unaudited Interim Financial Information
	The accompanying balance sheet as of December 31, 2014, was derived from the Company’s audited financial statements included in Form 10-K filed on March 27, 2015.  It is suggested that interim unaudited financial statements be read in conjunction with the annual financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K filed.
	The accompanying balance sheet as of March 31, 2015, the statements of operations for the three months ended March 31, 2015 and 2014, the statements of comprehensive loss for the three months ended March 31, 2015 and 2014, the statement of stockholders’ equity for the three months ended March 31, 2015 and the statements of cash flows for the three months ended March 31, 2015 and 2014 are unaudited.
	The interim unaudited financial statements have been prepared on the same basis as the annual audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of March 31, 2015 and the results of its operations for the three months ended March 31, 2015 and 2014 as well as its cash flows for the three months ended March 31, 2015 and 2014.
	The interim unaudited financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission.  Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading.
	Significant Accounting Policies
	The Company’s significant accounting policies are disclosed in the audited financial statements for the year ended December 31, 2014 included in the Company’s Form 10-K filed on March 27, 2015 with the SEC.  Since the date of such financial statements, there have been no changes to the Company’s significant accounting policies.
	Reclassifications
	Certain reclassifications were made to prior period amounts to correct the previous presentation.  During the three months ended March 31, 2014, $56,000 of certain expenses that had been previously classified as general and administrative were reclassified into research and development.

Net_Loss_Per_Common_Share

Net Loss Per Common Share	3 Months Ended
	Mar. 31, 2015
Net Loss Per Common Share
Net Loss Per Common Share
	3.Net Loss Per Common Share
	The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated (in thousands, except share and per share data):
		Three Months			Three Months
		Ended			Ended
		March 31,			March 31,
		2015			2014
	Basic and diluted net loss per common share calculation:
	Net loss	$	(6,182	)	$	(2,902	)
	Accretion of discount on redeemable convertible preferred stock	—			(11		)
	Net loss attributable to common stockholders	$	(6,182	)	$	(2,913	)
	Weighted average common shares outstanding — basic and diluted	16,474,269			204,807
	Net loss per share of common stock—basic and diluted	$	(0.38	)	$	(14.22	)
	The following outstanding securities at March 31, 2015 and 2014 have been excluded from the computation of diluted weighted average shares outstanding, as they would have been anti-dilutive:
		2015		2014
	Redeemable convertible preferred stock	—		5,656,949
	Unvested restricted stock	154,110		264,190
	Stock options	2,030,042		688,482
		2,184,152		6,609,621

Fair_Value_Investments

Fair Value Investments	3 Months Ended
	Mar. 31, 2015
Fair Value Investments.
Fair Value Investments
	4.Fair Value Investments
	Financial Instruments
	The financial instruments recorded in the Company’s balance sheets include cash and cash equivalents, investments, and accounts payable.
	Included in cash and cash equivalents are money market funds representing a type of mutual fund required by law to invest in low-risk securities (for example, U.S. government bonds, U.S. Treasury Bills and commercial paper) and overnight repurchase agreements.  Money market funds are structured to maintain the fund’s net asset value at $1.00 per unit, which assists in providing adequate liquidity upon demand by the holder.  Money market funds pay dividends that generally reflect short-term interest rates.  Thus, only the dividend yield fluctuates.  Also included in cash and cash equivalents are U.S.  Government sponsored enterprise debt securities that have a maturity of 3 months or less from their original acquisition date.  Due to their short-term maturity, the carrying amounts of cash and cash equivalents (including money market funds), and accounts payable approximate their fair values.  The Company classifies its remaining investments as available-for-sale.  Gains or losses on securities sold are based on the specific identification method.
	For investments classified as available-for-sale, the Company records unrealized gains or losses resulting from changes in fair value between measurement dates as a component of other comprehensive income (loss).
	(amounts in thousands)		Amortized		Gross		Gross			Fair Value
			Cost		Unrealized		Unrealized
					Gains		(Losses)
	March 31, 2015
	Overnight repurchase agreements		$	15,000	$	—	$	—		$	15,000
	Money market funds		9,588		—		—			9,588
	Total included in cash and cash equivalents		24,588		—		—			24,588
	Government enterprise debt securities
	Short-term available-for-sale securities		59,703		—		(6		)	59,697
	Long-term available-for-sale securities		9,651		—		(1		)	9,650
	Total		69,354		—		(7		)	69,347
	US Government debt securities
	Short-term available-for-sale securities		1,000		—		—			1,000
	Total		1,000		—		—			1,000
	Total fair value financial instruments		$	94,942	$	—	$	(7	)	$	94,935
	December 31, 2014
	Government enterprise debt securities		$	17,009	$	—	$	—		$	17,009
	Money market funds		8,846		—		—			8,846
	Total included in cash and cash equivalents		25,855		—		—			25,855
	Government enterprise debt securities
	Short-term available-for-sale securities		62,387		—		(25		)	62,362
	Long-term available-for-sale securities		6,651		—		(3		)	6,648
	Total		69,038		—		(28		)	69,010
	Total fair value financial instruments		$	94,893	$	—	$	(28	)	$	94,865
	Fair value guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value.  These tiers include:
		·		Level 1—Quoted prices in active markets for identical assets or liabilities.
		·		Level 2—Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.
		·		Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.
	The Company’s financial assets measured at fair value on a recurring basis at March 31, 2015 were as follows (in thousands):
			Fair Value Measurements at Measurement Date:
			Quoted Prices in Active		Significant Other		Significant Unobservable			Total As Of
			Markets for Identical Assets		Observable Inputs		Inputs			March 31, 2015
			(Level 1)		(Level 2)		(Level 3)
	Assets:
	Government enterprise debt securities		$	—	$	69,347	$	—		$	69,347
	Overnight repurchase agreements		15,000		—		—			15,000
	Money market funds		9,588		—		—			9,588
	US Government debt securities		1,000		—		—			1,000
	Totals		$	25,588	$	69,347	$	—		$	94,935
	The Company’s financial assets measured at fair value on a recurring basis at December 31, 2014 were as follows (in thousands):
			Fair Value Measurements at Measurement Date:
			Quoted Prices in Active		Significant Other		Significant Unobservable			Total As Of
			Markets for Identical Assets		Observable Inputs		Inputs			December 31, 2014
			(Level 1)		(Level 2)		(Level 3)
	Assets:
	Government enterprise debt securities		$	—	$	86,019	$	—		$	86,019
	Money market funds		8,846		—		—			8,846
	Totals		$	8,846	$	86,019	$	—		$	94,865
	There were no items that were accounted for at fair value on a non-recurring basis for the three months ended March 31, 2015 and 2014.
	Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and investments.  At March 31, 2015 and December 31, 2014, the Company’s cash and cash equivalents were held by two financial institutions and the amounts on deposit were in excess of FDIC insurance limits.  The Company mitigates this risk by depositing its uninsured cash in major well capitalized financial institutions, and by investing excess operating cash in overnight repurchase agreements which are 100% collateralized by U.S. Government backed securities with the Company’s bank.  The Company has not recognized any losses on its cash and cash equivalents.

Accrued_Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2015
Accrued Expenses.
Accrued Expenses
	5.Accrued Expenses
	Accrued expenses and other current liabilities consisted of the following (in thousands):
		March 31,		December 31,
		2015		2014
	Research and development expenses	$	525	$	742
	General and administrative expenses	462		769
	Share repurchase obligation	37		37
		$	1,024	$	1,548

Stock_Based_Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2015
Stock-Based Compensation
Stock-Based Compensation
	6.Stock-Based Compensation
	Effective July 2013, the Company adopted the 2013 Equity Incentive Plan, which was amended in November 2013 (the “2013 Plan”). The 2013 Plan provided for the granting of incentive stock options, non-statutory stock options and the issuance of restricted stock awards. As of March 31, 2015, the Company reserved for 1,544,615 shares of common stock authorized for issuance in connection with the 2013 Plan.  Certain options are eligible for exercise prior to vesting. Exercised but unvested shares are subject to repurchase by the Company at the initial exercise price.  In connection with the Company’s initial public offering, no further grants will be made under this plan and all remaining shares available for grant were transferred to the 2014 Equity Incentive Plan.
	The Company adopted a 2014 Equity Incentive Plan (the “2014 Plan”) that became effective on July 30, 2014 and serves as the successor to the 2013 Plan. The 2014 Plan provides for the grant of awards to employees, directors, consultants, independent contractors and advisors, provided the consultants, independent contractors, directors and advisors are natural persons that render services not in connection with the offer and sale of securities in a capital-raising transaction.  The exercise price of stock options must be at least equal to the fair market value of our common stock on the date of grant.
	The Company has reserved 1,591,106 shares of its common stock to be issued under the 2014 Plan of which 990,847 shares were available for future issuance as of March 31, 2015.  Shares will increase automatically on January 1 of each of 2015 through 2024 by the number of shares equal to 3.0% of the aggregate number of outstanding shares of our common stock as of the immediately preceding December 31.  The Company’s Board may reduce the amount of the increase in any particular year.  The 2014 Plan authorizes the award of stock options, restricted stock awards, or RSAs, stock appreciation rights, or SARs, restricted stock units, or RSUs, performance awards and stock bonuses.
	Certain options are eligible for exercise prior to vesting.  Exercised but unvested shares are subject to repurchase by the Company at the initial exercise price.  The proceeds from the shares subject to repurchase are classified as a liability and reclassified to equity as the shares vest.  Under the 2013 Equity Incentive Plan’s early exercise feature, the Company could be required to repurchase 10,156 shares as of March 31, 2015.  The Company records cash received from early exercised shares as a liability.  As of March 31, 2015, $37,000 has been recorded as a liability and included in accrued expenses.
	The following table summarizes stock option activity under the 2014 Plan for the period from January 1, 2015 through March 31, 2015:
								Average
						Weighted-		Remaining	Aggregate
			Number			Average		Contractual	Intrinsic Value
			of Shares			Exercise Price		Term (in years)	(in thousands)
	Outstanding at January 1, 2015		2,011,005			$	6.75	9.47	$	11,375
	Granted		35,225			12.38
	Exercised		—			—
	Cancelled		—			—
	Forfeited		(16,188		)	13.67
	Outstanding at March 31, 2015		2,030,042			$	6.79	9.23	$	12,304
	Vested and expected to vest at March 31, 2015		1,946,254			$	6.74	9.23	$	11,896
	Exercisable at March 31, 2015		659,423			$	3.4	8.92	$	6,037
	Weighted-average grant date fair value of options granted during the three months ended March 31, 2015		$	9.09
	As of March 31, 2015, there was $13.3 million of total unrecognized compensation expense related to options granted but not yet vested of which $3.1 million is attributable to non-employee awards and subject to re-measurement until vested.  The total unrecognized compensation expense of $13.3 million will be recognized as expense over a weighted-average period of 3.24 years.
	The Company uses the Black-Scholes option pricing model to estimate the fair value of option awards with the following weighted-average assumptions, which are based on industry comparative information, for the period indicated:
			Three Months
			Ended
			March 31, 2015
	Risk-free interest rate		1.59	%
	Expected dividend yield		0.00	%
	Expected stock price volatility		88.20	%
	Expected term of options (in years)		6.04
	Expected forfeiture rate		6.59	%
	The weighted-average valuation assumptions were determined as follows:
		·		Risk-free interest rate: The Company bases the risk-free interest rate on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the assumed expected option term.
		·		Expected annual dividends: The estimate for annual dividends is 0%, because the Company has not historically paid, and does not expect for the foreseeable future to pay, a dividend.
		·		Expected stock price volatility: The expected volatility used is based on historical volatilities of similar entities within the Company’s industry which were commensurate with the Company’s expected term assumption.
		·		Expected term of options: The expected term of options represents the period of time options are expected to be outstanding.  The expected term of the options granted to employees is derived from the “simplified” method as described in Staff Accounting Bulletin 107 relating to stock-based compensation.  The expected term for options granted to non-employees is equal to the contractual term of the awards.
		·		Expected forfeiture rate: The Company’s estimated annual forfeiture rate was 6.59%, based on historical forfeiture experience of its various employee groups.
		·		Estimated fair value of the Company’s stock-based awards: The estimated fair value of the Company’s stock-based awards is amortized on a straight-line basis over the awards’ service period for those awards with graded vesting and which contain only a service condition.  For awards with graded vesting and a performance and service condition, when achievement of the performance condition is deemed probable, the Company recognizes compensation cost using the accelerated recognition method over the awards’ service period.
	Share-based compensation expense recognized was as follows (in thousands):
			Three Months			Three Months
			Ended March 31,			Ended March 31,
			2015			2014
	Research and development		$	462		$	44
	General and administrative		587			20
			$	1,049		$	64

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies.
Commitments and Contingencies
	7.Commitments and Contingencies
	Array Collaboration Agreement
	On July 3, 2013, the Company signed a multi-year strategic collaboration agreement with Array, and this agreement was subsequently amended on November 26, 2013, April 10, 2014, October 13, 2014 and March 31, 2015.  The March 31, 2015 amendment was to provide additional full-time equivalents and other support dedicated to the conduct of the discovery, preclinical and clinical development programs for the remainder of 2015.
	Under the terms of the collaboration agreement, the Company obtained certain rights to Array’s tropomyosin receptor kinase (TRK) inhibitor program, as well as additional novel oncology targets, including rearranged during transfection (RET), fibroblast growth factor receptor (FGFR) and FMS-like tyrosine kinase 3 (FLT3).  The Company has worldwide commercial rights to each product candidate from the collaboration and Array participates in any potential successes through milestones, royalties, and an equity ownership in the Company.
	With respect to the discovery and preclinical program, the collaboration agreement runs through July 3, 2016, and the Company has the option to extend the term for up to two additional one-year renewal periods by providing written notice to Array at least three months before the end of the initial discovery and preclinical development programs or the renewal period, if applicable.  In addition to LOXO-101, the parties designated 12 discovery targets, of which seven were selected for additional study in January 2015, which will be reduced to four on or before January 2016.  The Company has the option to increase the total candidate selection number to five for a modest additional payment.
	As part of the agreement the Company agreed to pay Array a fixed amount per month, based on Array’s commitment to provide full-time equivalents and other support relating to the conduct of the discovery and preclinical development programs.  See Note 8 for amounts the Company recorded in related-party research and development expenses.
	Milestones
	With respect to product candidates directed to TRK, including LOXO-101 and its back-up compounds, the Company could be required to pay Array up to $222 million in milestone payments, the substantial majority of which are due upon the achievement of commercial milestones.  With respect to product candidates directed to targets other than TRK, the Company could be required to pay Array up to $213 million in milestone payments, the substantial majority of which are due upon the achievement of commercial milestones.
	Royalties
	The Company is required to pay Array mid-single digit royalties on worldwide net sales of products.  With respect to the royalty on products directed to targets other than TRK, the Company has the right to credit certain milestone payments against royalties on sales of products directed to such target.
	Research and Development Arrangements
	In the course of normal business operations, the Company enters into agreements with contract service organizations, or CROs, to assist in the performance of research and development and preclinical activities.  Expenditures to CROs may represent a significant portion of preclinical development costs for the Company in future periods.  The Company can elect to discontinue the work under these agreements at any time.  The Company could also enter into additional collaborative research, contract research, manufacturing, and supplier agreements in the future, which may require upfront payments and even long-term commitments of cash.
	Legal Proceedings
	The Company is not involved in any legal proceeding that it expects to have a material effect on its business, financial condition, results of operations or cash flows.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2015
Related Party Transactions
Related Party Transactions
	8.Related Party Transactions
	The Company recorded related-party research and development expenses of $1.9 million and $1.3 million for the three months ended March 31, 2015 and 2014, respectively, for services provided by Array under a collaboration agreement.  As of March 31, 2015, the Company had $0.7 million in prepaid expenses to Array under the collaboration agreement for services that will be provided in subsequent periods and $40,000 in accrued expenses already incurred.
	Dr. Lori Kunkel, a board member, has a consulting agreement with the Company to assist in the Company’s drug development process.  Dr. Kunkel is eligible to receive a maximum of $15,000 monthly for her consulting work.  Payments are expensed as incurred and recorded as a component of research and development expenses.  During the three months ended March 31, 2015, the Company recognized expenses of $45,000 in accordance with the terms of the consulting agreement.  As of March 31, 2015, there was $15,000 included in accrued expenses to Dr. Kunkel.

Subsequent_Event

Subsequent Event	3 Months Ended
	Mar. 31, 2015
Subsequent Event.
Subsequent Event
	9.Subsequent Event
	Effective May 1, 2015, the Company announced that Jennifer Burstein was appointed as the Vice President of Finance.  As Vice President of Finance, Ms. Burstein will serve as the Company’s principal financial officer and principal accounting officer.  Pursuant to the terms of the Transition and Separation Agreement entered into as of March 19, 2015 by the Company and Dov Goldstein, M.D., Dr. Dov Goldstein has stepped down as Acting Chief Financial Officer of Loxo, effective May 1, 2015.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies
Basis of Presentation
	Basis of Presentation
	The accompanying financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”).  Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”).
Unaudited Interim Financial Information
	Unaudited Interim Financial Information
	The accompanying balance sheet as of December 31, 2014, was derived from the Company’s audited financial statements included in Form 10-K filed on March 27, 2015.  It is suggested that interim unaudited financial statements be read in conjunction with the annual financial statements and the notes thereto included in the Company’s latest annual report on Form 10-K filed.
	The accompanying balance sheet as of March 31, 2015, the statements of operations for the three months ended March 31, 2015 and 2014, the statements of comprehensive loss for the three months ended March 31, 2015 and 2014, the statement of stockholders’ equity for the three months ended March 31, 2015 and the statements of cash flows for the three months ended March 31, 2015 and 2014 are unaudited.
	The interim unaudited financial statements have been prepared on the same basis as the annual audited financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of March 31, 2015 and the results of its operations for the three months ended March 31, 2015 and 2014 as well as its cash flows for the three months ended March 31, 2015 and 2014.
	The interim unaudited financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission.  Certain information and note disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to those rules and regulations, although the Company believes that the disclosures made are adequate to make the information not misleading
Significant Accounting Policies
	Significant Accounting Policies
	The Company’s significant accounting policies are disclosed in the audited financial statements for the year ended December 31, 2014 included in the Company’s Form 10-K filed on March 27, 2015 with the SEC.  Since the date of such financial statements, there have been no changes to the Company’s significant accounting policies.
Reclassifications
	Reclassifications
	Certain reclassifications were made to prior period amounts to correct the previous presentation.  During the three months ended March 31, 2014, $56,000 of certain expenses that had been previously classified as general and administrative were reclassified into research and development.

Net_Loss_Per_Common_Share_Tabl

Net Loss Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2015
Net Loss Per Common Share
Schedule of computation of basic and diluted net loss per share
	The following table sets forth the computation of basic and diluted net loss per common share for the periods indicated (in thousands, except share and per share data):
		Three Months			Three Months
		Ended			Ended
		March 31,			March 31,
		2015			2014
	Basic and diluted net loss per common share calculation:
	Net loss	$	(6,182	)	$	(2,902	)
	Accretion of discount on redeemable convertible preferred stock	—			(11		)
	Net loss attributable to common stockholders	$	(6,182	)	$	(2,913	)
	Weighted average common shares outstanding — basic and diluted	16,474,269			204,807
	Net loss per share of common stock—basic and diluted	$	(0.38	)	$	(14.22	)
Schedule of outstanding securities excluded from the computation of diluted weighted average shares outstanding, as they would have been anti-dilutive
		2015		2014
	Redeemable convertible preferred stock	—		5,656,949
	Unvested restricted stock	154,110		264,190
	Stock options	2,030,042		688,482
		2,184,152		6,609,621

Fair_Value_Investments_Table

Fair Value Investments (Table)	3 Months Ended
	Mar. 31, 2015
Fair Value Investments.
Schedule of available-for-sale securities unrealized gains and losses from changes in fair value
	(amounts in thousands)	Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		(Losses)
	March 31, 2015
	Overnight repurchase agreements	$	15,000	$	—	$	—		$	15,000
	Money market funds	9,588		—		—			9,588
	Total included in cash and cash equivalents	24,588		—		—			24,588
	Government enterprise debt securities
	Short-term available-for-sale securities	59,703		—		(6		)	59,697
	Long-term available-for-sale securities	9,651		—		(1		)	9,650
	Total	69,354		—		(7		)	69,347
	US Government debt securities
	Short-term available-for-sale securities	1,000		—		—			1,000
	Total	1,000		—		—			1,000
	Total fair value financial instruments	$	94,942	$	—	$	(7	)	$	94,935
	December 31, 2014
	Government enterprise debt securities	$	17,009	$	—	$	—		$	17,009
	Money market funds	8,846		—		—			8,846
	Total included in cash and cash equivalents	25,855		—		—			25,855
	Government enterprise debt securities
	Short-term available-for-sale securities	62,387		—		(25		)	62,362
	Long-term available-for-sale securities	6,651		—		(3		)	6,648
	Total	69,038		—		(28		)	69,010
	Total fair value financial instruments	$	94,893	$	—	$	(28	)	$	94,865
Schedule of financial assets measured at fair value on a recurring basis
	The Company’s financial assets measured at fair value on a recurring basis at March 31, 2015 were as follows (in thousands):
		Fair Value Measurements at Measurement Date:
		Quoted Prices in Active		Significant Other		Significant Unobservable			Total As Of
		Markets for Identical Assets		Observable Inputs		Inputs			March 31, 2015
		(Level 1)		(Level 2)		(Level 3)
	Assets:
	Government enterprise debt securities	$	—	$	69,347	$	—		$	69,347
	Overnight repurchase agreements	15,000		—		—			15,000
	Money market funds	9,588		—		—			9,588
	US Government debt securities	1,000		—		—			1,000
	Totals	$	25,588	$	69,347	$	—		$	94,935
	The Company’s financial assets measured at fair value on a recurring basis at December 31, 2014 were as follows (in thousands):
		Fair Value Measurements at Measurement Date:
		Quoted Prices in Active		Significant Other		Significant Unobservable			Total As Of
		Markets for Identical Assets		Observable Inputs		Inputs			December 31, 2014
		(Level 1)		(Level 2)		(Level 3)
	Assets:
	Government enterprise debt securities	$	—	$	86,019	$	—		$	86,019
	Money market funds	8,846		—		—			8,846
	Totals	$	8,846	$	86,019	$	—		$	94,865

Accrued_Expenses_Tables

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2015
Accrued Expenses.
Schedule of Accrued Expenses and Other Current Liabilities
	Accrued expenses and other current liabilities consisted of the following (in thousands):
		March 31,		December 31,
		2015		2014
	Research and development expenses	$	525	$	742
	General and administrative expenses	462		769
	Share repurchase obligation	37		37
		$	1,024	$	1,548

Stock_Based_Compensation_Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Stock-Based Compensation
Summary of stock option activity under the 2014 Plan
							Average
					Weighted-		Remaining	Aggregate
		Number			Average		Contractual	Intrinsic Value
		of Shares			Exercise Price		Term (in years)	(in thousands)
	Outstanding at January 1, 2015	2,011,005			$	6.75	9.47	$	11,375
	Granted	35,225			12.38
	Exercised	—			—
	Cancelled	—			—
	Forfeited	(16,188		)	13.67
	Outstanding at March 31, 2015	2,030,042			$	6.79	9.23	$	12,304
	Vested and expected to vest at March 31, 2015	1,946,254			$	6.74	9.23	$	11,896
	Exercisable at March 31, 2015	659,423			$	3.4	8.92	$	6,037
	Weighted-average grant date fair value of options granted during the three months ended March 31, 2015	$	9.09
Schedule of weighted-average assumptions under the Black-Scholes option pricing model estimate the fair value of option awards
		Three Months
		Ended
		March 31, 2015
	Risk-free interest rate	1.59	%
	Expected dividend yield	0.00	%
	Expected stock price volatility	88.20	%
	Expected term of options (in years)	6.04
	Expected forfeiture rate	6.59	%
Schedule of Share-based compensation expense recognized
	Share-based compensation expense recognized was as follows (in thousands):
		Three Months			Three Months
		Ended March 31,			Ended March 31,
		2015			2014
	Research and development	$	462		$	44
	General and administrative	587			20
		$	1,049		$	64

Organization_and_Description_o1

Organization and Description of the Business (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
	item	item
Organization and Description of the Business
Number of operating segments	1	1
Working capital	$97,900,000
Accumulated deficit	37,144,000	30,962,000
Cash, cash equivalents and investments	$107,600,000

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Summary of Significant Accounting Policies
General and administrative expenses reclassified into research and development	$56,000

Net_Loss_Per_Common_Share_Deta

Net Loss Per Common Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic and diluted net loss per common share calculation:
Net loss	($6,182)	($2,902)
Accretion of discount on redeemable convertible preferred stock		-11
Net loss attributable to common stockholders	($6,182)	($2,913)
Weighted average common shares outstanding-basic and diluted (in shares)	16,474,269	204,807
Net loss per share of common stock-basic and diluted (in dollars per share)	($0.38)	($14.22)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	2,184,152	6,609,621
Redeemable convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)		5,656,949
Unvested restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	154,110	264,190
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total (in shares)	2,030,042	688,482

Fair_Value_Investments_Detail

Fair Value Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Per Share data, unless otherwise specified
Net asset value for money market funds (in dollars per unit)	$1	$1
Overnight repurchase Agreements Member
Amortized Cost	$15,000
Fair Value	15,000
US Government-sponsored Enterprises Debt Securities
Amortized Cost		17,009
Fair Value		17,009
Money Market Funds
Amortized Cost	9,588	8,846
Fair Value	9,588	8,846
Cash and cash equivalents
Amortized Cost	24,588	25,855
Fair Value	24,588	25,855
Government enterprise Short-term available-for-sale securities
Amortized Cost	59,703	62,387
Gross Unrealized (Losses)	-6	-25
Fair Value	59,697	62,362
Government enterprise Long-term available-for-sale securities
Amortized Cost	9,651	6,651
Gross Unrealized (Losses)	-1	-3
Fair Value	9,650	6,648
Government enterprise AFS securities
Amortized Cost	69,354	69,038
Gross Unrealized (Losses)	-7	-28
Fair Value	69,347	69,010
US Government Short Term Available for Sale
Amortized Cost	1,000
Fair Value	1,000
US Government Debt Securities
Amortized Cost	1,000
Fair Value	1,000
Available-for-sale securities.
Amortized Cost	94,942	94,893
Gross Unrealized (Losses)	-7	-28
Fair Value	$94,935	$94,865

Fair_Value_Investments_Detail_

Fair Value Investments (Detail 2) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
	Institution	Institution
Number of financial institutions that hold cash and cash equivalents for the Company	2	2
Percentage of repurchase agreements collateralized by US Government backed securities (as a percent)	100.00%	100.00%
Recurring
Available-for-sale	94,935	94,865
Non-recurring
Investments	0		0
Fair Value, Inputs, Level 1 | Recurring
Available-for-sale	25,588	8,846
Fair Value, Inputs, Level 2 | Recurring
Available-for-sale	69,347	86,019
US Government-sponsored Enterprises Debt Securities | Recurring
Available-for-sale	69,347	86,019
US Government-sponsored Enterprises Debt Securities | Fair Value, Inputs, Level 2 | Recurring
Available-for-sale	69,347	86,019
Overnight repurchase Agreements Member | Recurring
Available-for-sale	15,000
Overnight repurchase Agreements Member | Fair Value, Inputs, Level 1 | Recurring
Available-for-sale	15,000
Money Market Funds | Recurring
Available-for-sale	9,588	8,846
Money Market Funds | Fair Value, Inputs, Level 1 | Recurring
Available-for-sale	9,588	8,846
US Government Debt Securities | Recurring
Available-for-sale	1,000
US Government Debt Securities | Fair Value, Inputs, Level 1 | Recurring
Available-for-sale	1,000

Accrued_Expenses_Detail

Accrued Expenses (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Accrued Expenses and Other Current Liabilities
Accrued Expenses	$1,024,000	$1,548,000
Research and development
Accrued Expenses and Other Current Liabilities
Accrued Expenses	525,000	742,000
General and administrative
Accrued Expenses and Other Current Liabilities
Accrued Expenses	462,000	769,000
Shares repurchase obligation
Accrued Expenses and Other Current Liabilities
Accrued Expenses	$37,000	$37,000

Stock_Based_Compensation_Detai

Stock Based Compensation (Details) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	Jul. 02, 2014
2013 Plan
2013 and 2014 Equity Incentive Plan
Shares authorized for issuance	1,544,615
Shares available for future issuance (in shares)	0
Shares that could be required to be repurchased (in shares)	10,156
Shares subject to repurchase liability, amount recorded in accrued expenses	$37,000
2014 Plan
2013 and 2014 Equity Incentive Plan
Shares authorized for issuance	1,591,106
Shares available for future issuance (in shares)	990,847
Increase in common stock reserved for issuance as percentage of the aggregate number of outstanding shares of common stock (as a percent)		3.00%

Stock_Based_Compensation_Detai1

Stock Based Compensation (Details 2) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
2013 and 2014 Equity Incentive Plans | Stock option
Weighted average assumptions used to estimate fair value of option awards using Black Scholes option pricing model
Unrecognized compensation expense	$13,300,000
2014 Plan | Stock option
Number of Shares
Outstanding at the beginning of the period (in shares)	2,011,005
Granted (in shares)	35,225
Forfeited (in shares)	-16,188
Outstanding at the end of the period (in shares)	2,030,042	2,011,005
Vested and expected to vest at the end of the period (in shares)	1,946,254
Exercisable at the end of the period (in shares)	659,423
Weighted average grant date fair value of options granted (in dollars per share)	$9.09
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$6.75
Granted (in dollars per share)	$12.38
Forfeited (in dollars per share)	$13.67
Outstanding at the end of the period (in dollars per share)	$6.79	$6.75
Vested and expected to vest at the end of the period (in dollars per share)	$6.74
Exercisable at the end of the period (in dollars per share)	$3.40
Average Remaining Contractual Term
Outstanding at the beginning of the period	9 years 2 months 23 days	9 years 5 months 19 days
Outstanding at the end of the period	9 years 2 months 23 days	9 years 5 months 19 days
Vested and expected to vest at the end of the period	9 years 2 months 23 days
Exercisable at the end of the period	8 years 11 months 1 day
Aggregate Intrinsic Value
Outstanding at the end of the period	12,304,000	11,375,000
Vested and expected to vest at the end of the period	11,896,000
Exercisable at the end of the period	6,037,000
Weighted average assumptions used to estimate fair value of option awards using Black Scholes option pricing model
Risk-free interest rate	1.59%
Expected dividend yield	0.00%
Expected stock price volatility	88.20%
Expected term of options (in years)	6 years 15 days
Expected forfeiture rate	6.59%
Weighted-average period for recognition	3 years 2 months 27 days
Non-employees
Weighted average assumptions used to estimate fair value of option awards using Black Scholes option pricing model
Unrecognized compensation expense	$3,100,000

Stock_Based_Compensation_Detai2

Stock Based Compensation (Details 3) (2013 and 2014 Equity Incentive Plans, USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Stock based compensation expense
Share-based compensation expense	$1,049	$64
Research and development
Stock based compensation expense
Share-based compensation expense	462	44
General and administrative
Stock based compensation expense
Share-based compensation expense	$587	$20

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	0 Months Ended	3 Months Ended
	Oct. 13, 2014	Mar. 31, 2015	Mar. 31, 2014
	item
Commitments and contingencies
Related party research and development expenses		$1,918,000	$1,275,000
Collaboration agreement | Array
Commitments and contingencies
Term of additional renewal periods options available to the entity to extend agreement term (in options)		1 year
Number of discovery targets designated by the parties (in targets)	12
Number of discovery targets which are to be selected for additional study on or before January 2015 (in targets)	7
Number of discovery targets which are to be selected for additional study after reduction on or before January 2016 (in targets)	4
Maximum number of candidates which can be selected by the entity for modest additional payment (in candidates)	5
Related party research and development expenses		1,900,000	1,300,000
Collaboration agreement | Maximum | Array
Commitments and contingencies
Number of additional renewal periods options available to the entity to extend agreement term (in periods)		2
Collaboration agreement | Product candidates directed to TRK | Array
Commitments and contingencies
Maximum milestone payments which the entity could be required to pay		222,000,000
Collaboration agreement | Product candidates directed to targets other than TRK | Array
Commitments and contingencies
Maximum milestone payments which the entity could be required to pay		$213,000,000

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Oct. 23, 2014	Dec. 31, 2014
Related party transactions
Related party research and development expenses	$1,918,000	$1,275,000
Accrued Expenses	1,024,000			1,548,000
Dr. Lori Kunkel
Related party transactions
Maximum monthly fees for consulting work			15,000
Dr. Lori Kunkel | Accounts payable
Related party transactions
Accrued expenses to related parties	15,000
Dr. Lori Kunkel | Research and development
Related party transactions
Expenses recognized for consulting work	45,000
Collaboration agreement | Array
Related party transactions
Related party research and development expenses	1,900,000	1,300,000
Accrued Expenses	40,000
Prepaid expenses	$700,000