Stock-Based Compensation Expense (Tables)

3 Months Ended

Mar. 31, 2017

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

Schedule of Stock-Based Compensation Expense

Stock-based compensation expense for restricted stock, restricted stock units, stock options and issuances of common stock pursuant to our employee stock purchase plan was classified in the accompanying consolidated statements of operations as follows:

	Three Months Ended March 31,
	2017		2016
	(in thousands)
Stock-based compensation expense:
Cost of revenue	$	202	$	137
Research and development	1,513		1,493
Sales and marketing	1,403		2,901
General and administrative	1,161		988
Total stock-based compensation expense	$	4,279	$	5,519

Summary of Restricted Stock and Restricted Stock Unit Activity

Restricted stock and restricted stock unit activity during the three months ended March 31, 2017 was as follows:

	Restricted Stock				Restricted Stock Units
	Shares		Weighted-Average Grant Date Fair Value		Shares		Weighted-Average Grant Date Fair Value
Unvested balance as of December 31, 2016	585,004		$	18.05	734,577		$	13.47
Granted	—		—		1,308,940		13.83
Vested	(78,441	)	19.05		(48,312	)	13.21
Forfeited	(860	)	23.01		(40,554	)	12.73
Unvested balance as of March 31, 2017	505,703		$	17.89	1,954,651		$	13.73

Summary of Stock Option Activity

Stock option activity during the three months ended March 31, 2017 was as follows:

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (in years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2016	4,580,375		$	8.20
Granted	1,138,566		12.93
Exercised	(120,479	)	6.43			$	1,000
Forfeited/cancelled	(97,442	)	12.10
Outstanding as of March 31, 2017	5,501,020		9.15		7.3	$	32,817
Vested and exercisable as of March 31, 2017	2,926,282		5.91		5.6	$	26,759
Vested and expected to vest as of March 31, 2017	5,501,020		9.15		7.3	$	32,817