Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense

We record stock-based compensation expense (including stock options, restricted stock and employee stock purchase plan) to the same departments where cash compensation is recorded as follows (in thousands):

	Nine Months Ended September 30,
	2016		2015
Costs of revenue	$	789	$	810
Selling and marketing		1,140		1,024
Research and development		3,148		1,809
General and administrative		1,793		2,867
Total stock-based compensation expense	$	6,870	$	6,510

Assumptions Used to Determine the Fair Value of Options Granted under Employee Stock-Based Compensation Arrangements

We estimated the fair value of options granted under our employee stock-based compensation arrangements at the date of grant using the following weighted-average expected assumptions:  

	Nine Months Ended September 30,
	2016		2015
Dividend yield	None		None
Volatility		49%		49%
Risk-free interest rate		1.90%		1.70%
Expected life (years)	5.8		5.7