Equity Incentive Plans and Stock-Based Compensation (Details 3) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Stock Option [Member]
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum			40.00%
Valuation assumptions
Expected stock price volatility (as a percent)	40.00%	47.00%		47.00%
Risk free interest rate	2.20%	0.80%
Expected term	6 years 0 months 14 days	5 years 4 months 29 days		5 years 4 months 29 days
Weighted-average fair value of stock options granted (in dollars per share)	$ 4.95	$ 2.61	$ 3.98	$ 2.35
Weighted-Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum			44.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum			2.10%	0.80%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum			2.20%	0.90%
Employee Stock Purchase Plan
Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum			39.00%
Valuation assumptions
Expected stock price volatility (as a percent)				48.00%
Risk free interest rate				0.10%
Expected term				6 months
Weighted-average fair value of stock options granted (in dollars per share)			$ 3.91	$ 1.94
Weighted-Average Grant-Date Fair Value
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum			44.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum			0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum			0.10%
Restricted Stock and Stock Units [Member]
Nonvested equity stock and stock units
Nonvested at the beginning of the period (in shares)			629,649
Granted (in shares)	22,868	28,456	228,676	304,952
Vested (in shares)			(128,220)
Forfeited (in shares)			(23,115)
Nonvested at the end of the period (in shares)	706,990		706,990
Weighted-Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)			$ 8.56
Granted (in dollars per share)			$ 9.08
Vested (in dollars per share)			$ 9.26
Forfeited (in dollars per share)			$ 6.86
Nonvested at the end of the period (in dollars per share)	$ 8.65		$ 8.65
Minimum | Employee Stock Option [Member]
Valuation assumptions
Expected term			6 years 0 months 14 days
Minimum | Employee Stock Purchase Plan
Valuation assumptions
Expected term			0 years 0 months 7 days
Maximum | Employee Stock Option [Member]
Valuation assumptions
Expected term			6 years 0 months 29 days
Maximum | Employee Stock Purchase Plan
Valuation assumptions
Expected term			6 months