Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

The following table summarizes the status of the Company’s stock option activity granted under the Plans to employees, directors, and consultants (in thousands, except stock option amounts and exercise price):

	Stock Options			Weighted- Average Exercise price		Weighted- Average Remaining Contractual Term		Aggregate Intrinsic Value
Outstanding at December 31, 2017		10,176,643		$	7.19		6.83	$	88,615
Granted		1,411,650			17.25
Exercised		(607,655	)		5.59
Forfeited and expired		(194,135	)		10.77
Outstanding at September 30, 2018		10,786,503		$	8.53		6.64	$	75,562
Vested and exercisable at September 30, 2018		7,808,020		$	6.51		5.80	$	70,511

Schedule of Weighted Average Assumptions Used as Inputs to Black-Scholes Model

The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model during the periods indicated:

	Nine Months Ended			Nine Months Ended
	September 30, 2018			September 30, 2017
Weighted average grant date fair value	$	9.87		$	6.90
Expected dividend yield		—	%		—	%
Expected stock price volatility		59	%		66	%
Risk-free interest rate		2.60	%		1.74	%
Expected life of options (in years)		6.1			6.2

Schedule of Stock-Based Compensation Expense

The components of stock-based compensation and the amounts recorded within research and development expenses and selling, general, and administrative expenses in the Company’s consolidated statements of operations and comprehensive loss consisted of the following for the three and nine months ended September 30, 2018 and 2017 (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2018		2017		2018		2017
Stock options	$	2,316	$	2,349	$	7,558	$	5,690
Vesting of restricted stock grants		6		540		1,007		1,620
Stock awarded to directors and officers		—		—		—		4,400
Employee stock purchase plan		94		—		94		—
Total stock-based compensation expense	$	2,416	$	2,889	$	8,659	$	11,710
Cost of sales	$	64	$	48	$	164	$	96
Research and development expenses		688		567		1,915		1,475
Selling, general, and administrative expenses		1,664		2,274		6,580		10,139
Total stock-based compensation expense	$	2,416	$	2,889	$	8,659	$	11,710