Stockholders' Equity

3 Months Ended

Mar. 31, 2019

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

In conjunction with our 2025 notes offering in March 2019, we repurchased 504,286 shares of our common stock at an average price per share of $39.66.

Share-based Compensation Expense

Total share-based compensation expense recorded for employees and non-employees, is as follows (in thousands):



	Three Months Ended March 31,
	2019		2018
Cost of revenues	$	125	$	94
Research and development	4,917		4,133
Sales and marketing	1,808		1,589
General and administrative	8,188		5,826
Total share-based compensation expense	$	15,038	$	11,642

RSU and PSU Activity

Activity for RSUs and PSUs is as follows:



	RSUs and PSUs Outstanding
	Number of RSUs and PSUs Outstanding		Weighted Average Grant Date Fair Value
Balance at December 31, 2018	10,804,808		$	11.87
Granted	1,440,428		39.95
Released	(4,352,468	)	8.97
Canceled	(727,939	)	7.12
Balance at March 31, 2019	7,164,829		$	19.76

As of March 31, 2019, our total unrecognized share-based compensation expense related to RSUs and PSUs was approximately $98.1 million, which will be recognized over the remaining weighted-average vesting period of approximately 1.9 years.