Employee benefit plans (Tables)

A summary of the Company’s PSU activity for the six months ended June 30, 2020 is as follows:


	Shares (in thousands)	Weighted-average grant date fair value
Non-vested shares at December 31, 2019	788	$	7.51
Granted	1,221	4.04
Vested	(179)	7.51
Forfeited	(205)	7.02
Non-vested shares at June 30, 2020	1,625	$	4.97

A summary of the Company’s stock option activity for the six months ended June 30, 2020 is as follows:


	Shares (in thousands)	Weighted-average exercise price		Weighted-average remaining contractual term (in years)	Aggregate intrinsic value (in thousands)




Outstanding at December 31, 2019	3,963	$	10.16	6.35	$	374
Granted	1,006	3.99
Exercised	(25)	1.13
Forfeited/Cancelled	(773)	9.88
Outstanding at June 30, 2020	4,171	$	8.78	6.59	$	1,064

Vested and expected to vest at June 30, 2020	4,171	$	8.78	6.59	$	1,064
Exercisable at June 30, 2020	2,676	$	10.93	5.12	$	324

A summary of the Company’s RSU activity for the six months ended June 30, 2020 is as follows:


	Shares (in thousands)	Weighted-average grant date fair value




Non-vested shares at December 31, 2019	8,225	$	6.11
Granted	5,604	4.09
Vested	(1,649)	6.78
Forfeited	(1,823)	5.50
Non-vested shares at June 30, 2020	10,357	$	5.02

The following table summarizes stock-based compensation expense included in the condensed consolidated statements of operations:


	Three months ended June 30,						Six months ended June 30,
(in thousands)	2020		2019		2020		2019
Cost of revenue	$	332	$	522	$	835	$	1,035
Research and development	3,063		4,884		6,085		9,561
Sales and marketing	789		2,221		2,506		4,434
General and administrative	1,692		2,979		4,087		5,361
Total stock-based compensation expense	$	5,876	$	10,606	$	13,513	$	20,391