Stock-based Awards

Stock Options

A summary of the Company’s stock option activity for the six months ended June 30, 2018 is as follows:



	Number of Options		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life
					(in years)
Outstanding at December 31, 2017	16,714,216		$	12.46	7.7
Granted	1,439,287		9.60
Exercised	(463,426	)	6.89
Canceled/forfeited	(1,002,936	)	14.03
Outstanding at June 30, 2018	16,687,141		$	12.28	7.0

At June 30, 2018, total remaining stock-based compensation expense for unvested stock option awards was $44.3 million, which is expected to be recognized over a weighted-average period of 2.8 years. For the three months ended June 30, 2018 and 2017, the Company recorded stock-based compensation expense for stock option awards of $3.8 million and $3.7 million, respectively. For the six months ended June 30, 2018 and 2017, the Company recorded stock-based compensation expense for stock option awards of $8.4 million and $7.0 million, respectively.

Restricted Stock Units

Activity in connection with restricted stock units is as follows for the six months ended June 30, 2018:



	Number of Shares		Weighted- Average Grant Date Fair Value
Non-vested — December 31, 2017	4,284,438		$	11.99
Granted	3,025,260		9.69
Vested	(852,017	)	11.24
Canceled/forfeited	(558,775	)	10.87
Non-vested — June 30, 2018	5,898,906		$	11.02

At June 30, 2018, total remaining stock-based compensation expense for non-vested restricted stock units is $61.7 million, which is expected to be recognized over a weighted-average period of 3.0 years. The Company recorded $5.2 million and $3.2 million in stock-based compensation expense for restricted stock units for the three months ended June 30, 2018 and 2017, respectively. The Company recorded $9.6 million and $5.8 million in stock-based compensation expense for restricted stock units for the six months ended June 30, 2018 and 2017, respectively.

Stock-based Compensation Cost

The Company recorded stock-based compensation cost relating to stock options and restricted stock awards in the following categories on the accompanying consolidated statements of comprehensive loss (in thousands):



	Three Months Ended June 30,				Six Months Ended June 30,
	2018		2017		2018		2017

Cost of revenue	$	443	$	233	$	741	$	436
Sales and marketing	3,543		2,160		6,670		3,905
Technology and development	2,698		1,600		5,051		2,898
General and administrative	2,288		2,853		5,607		5,514
Total stock-based compensation expense	8,972		6,846		18,069		12,753
Amount capitalized to internal software use	473		332		807		550
Total stock-based compensation cost	$	9,445	$	7,178	$	18,876	$	13,303