Stock-based Compensation and Awards (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Rollforward of stock option activity

A summary of the stock option activity for the six months ended June 30, 2020 is presented below:

	Options Outstanding
	Number of options		Weighted average exercise price		Weighted average remaining contractual term	Aggregate intrinsic value
					(in years)	(in thousands)
Outstanding at December 31, 2019	606,327		$	13.41	3.62	$	4,566
Options granted	—		—
Options exercised	(124,417	)	10.65
Options canceled	(1,700	)	9.40
Outstanding at June 30, 2020	480,210		$	14.15	3.09	$	3,542

Equity B-S-M Valuation Assumptions

The following Black-Scholes option-pricing assumptions were used for each respective period for the ESPP:

	Three months ended June 30,		Six months ended June 30,
	2020	2019	2020	2019
Expected term (in years)	0.50	0.50	0.50	0.50
Volatility	50% - 54.14%	33% - 45.2%	50% - 54.14%	33% - 45.2%
Risk-free interest rate	0.15% - 1.59%	2.43% - 2.51%	0.15% - 1.59%	2.43% - 2.51%
Dividend yield	0%	0%	0%	0%

Rollforward of RSA and RSU activty

A summary of RSU and PSU activity for the six months ended June 30, 2020 is presented below:

	Restricted Stock Units and Performance Stock Units
	Number of shares		Weighted Average Grant Date Fair Value per Share
Outstanding at December 31, 2019	1,550,646		$	28.94
Granted	1,308,571		21.91
Vested	(705,835	)	27.97
Forfeited	(28,158	)	28.03
Outstanding at June 30, 2020	2,125,224		$	24.95

PSU Valuation Assumptions

The assumptions used in the Monte Carlo valuation model to value the PSUs were as follows:

	June 30, 2020
Grant date fair value per share	$	30.70
Expected term (in years)	3
Volatility	42.68		%
Risk-free interest rate	0.20		%
Dividend yield	—		%

Allocation of Recognized Period Costs

The following table presents the allocation of stock-based compensation expense:

	Three months ended June 30,				Six months ended June 30,
(in thousands)	2020		2019		2020		2019
Cost of revenue	$	1,114	$	1,178	$	2,087	$	2,156
Research and development	1,023		1,034		1,989		1,856
Sales and marketing	1,961		1,758		3,821		3,478
General and administrative	2,268		2,139		4,310		4,163
Total stock-based compensation	$	6,366	$	6,109	$	12,207	$	11,653