Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2015

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

Stock-Based Compensation Expense

Total stock-based compensation expense recognized in our unaudited condensed consolidated statements of operations and comprehensive income (loss) includes amounts related to stock options, restricted stock units, and employee stock purchase plans and was as follows (in thousands):

	Quarters Ended March 31,
	2015		2014
Total stock-based compensation expense	$	1,329	$	1,337

Weighted-Average Assumptions Used to Determine Fair Value of Options Granted

The fair value of options granted determined using the Black-Scholes model used the following weighted-average assumptions:

	Quarters Ended March 31,
	2015		2014
Expected dividend yield	0	%	0	%
Risk-free interest rate	1.20	%	1.10	%
Expected life (years)	4.2		3.8
Volatility	37	%	40	%