Employee Equity-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Option Activity

The following table summarizes option activity under all plans during the six-month period ending June 30, 2017:

Stock Option Activity
	Number of Shares		Weighted Average Exercise Price per Share
Options outstanding December 31, 2016	6,857,124		7.72
Granted	1,054,561		24.54
Forfeited	(117,338	)	22.15
Exercised	(288,303	)	9.29
Expired	(1	)	18.07
Options Outstanding June 30, 2017	7,506,043		9.80

Black-Scholes Assumptions for Options Granted

The table below summarizes the resulting weighted average inputs used to calculate the estimated fair value of options awarded during the periods shown below:

Black-Scholes Assumptions for Options Granted
	Three Months Ended
	June 30, 2017			June 30, 2016
Expected term (in years)	6.12			6.20
Volatility	75		%	85		%
Expected dividends	—			—
Risk free interest rates	2.02		%	1.45		%
Weighted average fair value	$	16.80		$	9.66

Stock Option Supplemental Information

The following table shows summary information for outstanding options and options that are exercisable (vested) as of June 30, 2017:

Stock Option Supplemental Information
	Options Outstanding		Options Exercisable
Number of options	7,506,043		5,070,585
Weighted average remaining contractual term (in years)	6.56		5.60
Weighted average exercise price	$	9.80	$	5.73
Weighted average fair value	$	7.28	$	4.33
Aggregate intrinsic value (in thousands)	$	131,115	$	109,601

Restricted Stock Unit (RSU) Activity

The following table summarizes restricted stock unit activity during the six-month period ending June 30, 2017:

Restricted Stock Unit (RSU) Activity
	Number of Shares		Weighted Average Grant Date Fair Value per Share
RSUs Outstanding December 31, 2016	40,250		20.91
Granted	—		—
Forfeited	—		—
Vested/released	(16,100	)	20.91
RSUs outstanding June 30, 2017	24,150		20.91

Equity-Based Compensation Expenses

The expense recognized on the Company’s condensed consolidated statements of operations and comprehensive loss related to options is summarized below:

Equity-Based Compensation Expenses (in thousands)
	Three Months Ended				Six Months Ended
	June 30, 2017		June 30, 2016		June 30, 2017		June 30, 2016
Cost of sales	$	22	$	—	$	22	$	—
Research and development	1,166		462		1,892		664
Sales, general and administrative	3,047		1,773		5,536		3,257
Equity-based compensation expense	$	4,235	$	2,235	$	7,450	$	3,921