Stock-Based Awards (Tables)

9 Months Ended

Sep. 30, 2019

Summary of Stock Option Activity

The following table summarizes stock options activity for the nine months ended September 30, 2019 (in thousands):

	Number of Shares
Outstanding at December 31, 2018		3,603
Granted		558
Exercised		(424	)
Forfeited or expired		(362	)
Outstanding at September 30, 2019		3,375
Vested and exercisable at September 30, 2019		1,306

Summary of Stock-Based Compensation Expense

The following table presents the effects of stock-based compensation in our condensed consolidated statements of operations for the periods presented (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2019		2018		2019		2018
Cost of revenue	$	192	$	144	$	495	$	325
Research and development expense		1,717		1,039		4,028		2,620
Sales and marketing expense		1,622		1,188		4,028		2,876
General and administrative expense		1,262		964		3,262		2,192
Total stock-based compensation expense	$	4,793	$	3,335	$	11,813	$	8,013

Restricted Stock Units

Summary of Restricted Stock Units

The following table summarizes activity for restricted stock units, or RSUs, and RSUs with performance conditions, or PSUs, for the nine months ended September 30, 2019 (in thousands):

	Number of Shares
	RSUs			PSUs
Outstanding at December 31, 2018		32			—
Granted		462			248
Vested		(40	)		—
Forfeited		(4	)		(12	)
Outstanding at September 30, 2019		450			236