Stock-Based Compensation

3 Months Ended

Mar. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock Based Compensation

9. Stock Based Compensation

Stock Options

The following table summarizes stock option activity under our 2013 Equity Incentive Plan (the “2013 Plan”) and an Inducement Plan, and related information during the three months ended March 31, 2019:

	Shares
	Subject to			Weighted-
	Outstanding			Average Exercise
	Options			Price Per Share
Balance at December 31, 2018		7,507,690		$	33.25
Options granted		1,557,406			27.53
Options exercised		(424,589	)		17.84
Options canceled		(309,175	)		38.31
Balance at March 31, 2019		8,331,332		$	32.78

Performance Stock Options (“PSOs”)   

In March 2019, the Compensation Committee of our Board of Directors approved a program to award up to 490,986 PSOs to the management team based on the achievement of certain net revenue goals. The following table summarizes PSO activities under our 2013 Plan and related information during the three months ended March 31, 2019:

	Shares
	Subject to			Weighted-
	Outstanding			Average Exercise
	PSOs			Price Per Share
Balance at December 31, 2018		143,335		$	23.76
Options granted		490,986			33.29
Options exercised		(10,000	)		23.76
Options canceled		—			—
Balance at March 31, 2019		624,321		$	31.25

Restricted Stock Units (“RSUs”)

The following table summarizes RSU activity under our 2013 Plan and Inducement Plan, and related information during the three months ended March 31, 2019:

	Shares
	Subject to			Weighted-
	Outstanding			Average Grant Date
	RSUs			Fair Value Per Share
Balance at December 31, 2018		979,278		$	34.00
RSUs granted		559,287			27.64
RSUs released		(314,311	)		35.29
RSUs canceled		(44,774	)		36.51
Balance at March 31, 2019		1,179,480		$	30.55

Performance Stock Units(“PSUs”)

The following table summarizes PSU activity under our 2013 Plan and related information during the nine months ended March 31, 2019:

	Shares
	Subject to			Weighted-
	Outstanding			Average Grant Date
	PSUs			Fair Value Per Share
Balance at December 31, 2018		153,503		$	29.85
PSUs granted		—			—
PSUs released		(18,575	)		32.66
PSUs canceled		(26,801	)		28.67
Balance at March 31, 2019		108,127		$	29.66

The table below sets forth the functional classification of stock-based compensation expense for the periods presented (in thousands):  

	Three Months Ended March 31,
	2019			2018
Research and development	$	10,137		$	4,452
Selling, general and administrative		7,999			6,528
Subtotal	$	18,136		$	10,980
Capitalized stock-based compensation costs		(242	)		—
Stock-based compensation expense included in total expenses	$	17,894		$	10,980