Stock-Based Awards (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Activity Under Stock Option Plans Including 2011 Plan and 2014 Plan

Stock Option Activity

The following table summarizes activity under the Company’s stock option plans, including the 2011 Plan, the 2014 Plan, the assumed equity awards from the Dimension plans and related information:

	Options Outstanding
	Number of Options			Weighted- Average ExercisePrice		Weighted-Average Remaining Contractual Term(Years)		Aggregate Intrinsic Value
								(Inthousands)
Outstanding — December 31, 2014		2,739,475		$	16.15		8.43	$	79,840
Options granted		2,013,350			90.60
Options exercised		(795,825	)		8.65
Options cancelled		(130,037	)		31.49
Outstanding — December 31, 2015		3,826,963		$	56.36		8.58	$	217,386
Options granted		1,435,995			67.00
Options exercised		(425,922	)		21.21
Options cancelled		(407,564	)		70.87
Outstanding — December 31, 2016		4,429,472		$	61.85		8.22	$	79,135
Options granted		1,328,860			71.99
Options assumed		639,897			27.97
Options exercised		(478,470	)		16.25
Options cancelled		(520,349	)		78.70
Outstanding — December 31, 2017		5,399,410		$	62.75		7.40	$	37,687
Vested and exercisable — December 31, 2017		2,709,510		$	53.53		6.22	$	34,558
Vested and expected to vest — December 31,    2017		5,216,110		$	62.50		7.35	$	37,528

Summary of Activity Under Restricted Stock Units (RSUs) from 2014 Plan

The following table summarizes activity under the Company’s Restricted Stock Units (RSUs) from the 2014 Plan and related information:

	RSUs Outstanding
	Number of Shares			Weighted- Average Grant Date Fair Value
Unvested — December 31, 2014		31,000		$	53.23
RSUs granted		187,260			89.67
RSUs released		(18,209	)		54.72
RSUs cancelled		(2,900	)		84.89
Unvested — December 31, 2015		197,151		$	87.24
RSUs granted		477,816			66.83
RSUs released		(52,273	)		82.59
RSUs cancelled		(48,950	)		78.04
Unvested — December 31, 2016		573,744		$	71.45
RSUs granted		516,161			71.58
RSUs released		(156,021	)		71.93
RSUs cancelled		(112,324	)		76.78
Unvested — December 31, 2017		821,560		$	70.71

Summary of Stock-Based Compensation Recognized

Total stock-based compensation recognized was as follows (in thousands):

	Year Ended December 31,
	2017		2016		2015
Research and development	$	38,212	$	29,412	$	17,100
Selling, general and administrative		29,802		18,897		7,784
Total stock-based compensation expense	$	68,014	$	48,309	$	24,884

Fair Value of Stock Option Awards Granted Estimated Using Black-Scholes Option-Pricing Model

The fair value of stock option awards granted was estimated at the date of grant using a Black-Scholes option-pricing model with the following weighted-average assumptions:

	Year Ended December 31,
	2017	2016	2015
Expected term (years)	6.23	6.23	6.23
Expected volatility	65%	65%	65%
Risk-free interest rate	2.1%	1.5%	1.8%
Expected dividend rate	0.0%	0.0%	0.0%