Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2015

Schedule of Estimated Useful Lives of Property and Equipment

Property and equipment is stated at cost, and depreciated using the straight-line method over the estimated useful lives of the respective assets.


Laboratory equipment		5 years
Computer equipment and software		3 years
Leasehold improvements		Shorter of asset’s useful life or remaining term of lease
Build-to-suit property		10 years

Reconciliation of Net Loss to Net Loss Attributable to Common Stockholders

The following table reconciles net loss to net loss attributable to common stockholders (in thousands, except share and per share data):


	Three Months Ended March 31,
	2015			2014
Net loss	$	(64,965	)	$	(8,949	)
Weighted average number of common shares used in net loss per share – basic and diluted		82,507,813			6,330,843

Net loss per share – basic and diluted	$	(0.79	)	$	(1.41	)

Schedule of Diluted Net Loss Per Share Attributable to Common Stockholders Due to Anti-Dilutive Effect

The amounts in the table below were excluded from the calculation of diluted net loss per share attributable to common stockholders for the periods indicated due to their anti-dilutive effect:


	As of March 31,
	2015		2014
Series A convertible preferred stock		—		16,930,668
Series A-1 convertible preferred stock		—		2,250,000
Unvested restricted common stock		7,598,095		7,489,162
Options to purchase common stock		3,840,931		—
Estimated shares issued if success payment valuation occurred at March 31, 2015 (1)		3,379,492		—

Total		14,818,518		26,669,830

(1)

Represents the number of shares that would be issued if the success payment valuation date had been March 31, 2015. The Company’s common stock price per share was $60.66 at March 31, 2015 which would have resulted in a success payment of $205 million ($125 million for FHCRC and $80 million for MSK). The number of shares issued is calculated by dividing the $160 million success payment by the stock price of $60.66 at March 31, 2015. At March 31, 2014 the stock price was below the threshold that would require a payment to FHCRC or MSK, therefore no shares are included.