Share-Based Compensation - Additional Information (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of average closing price to be paid by employees			85.00%
Share-based compensation	$ 554,000	$ 436,000	$ 1,059,000	$ 810,000
Estimated pre-vesting forfeiture rate			5.50%
Weighted-average grant date fair value for stock options (in dollars per share)			$ 0	$ 5.32
Aggregate intrinsic value of stock options exercised			388,000	52,000
Cash receipts of stock options exercised			450,000	44,000
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock purchases through advance payroll deductions in a calendar year			25,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option term			10 years
Stock options vesting percentage			100.00%
Unrecognized compensation expense	15,000		15,000
Unrecognized compensation expense expected recognition period			0 years 7 months 22 days
Stock Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			6 months
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			2 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period			3 years
Unrecognized compensation expense	3,476,000		3,476,000
Unrecognized compensation expense expected recognition period			1 year 6 months 23 days
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	0		0
Grant date fair value of ESPP options			$ 24,000