Stock-Based Compensation - (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Stock-based compensation
Stock-based compensation expense	$ 1,200	$ 1,900	$ 2,100	$ 3,100
Accelerated compensation expenses		$ 1,100
Common stock, shares issued	29,134,000		29,134,000		29,025,000
Proceeds from exercise of stock options			$ 556	$ 1,665
Common Stock
Stock-based compensation
Common stock, shares issued	100,000		100,000
Proceeds from exercise of stock options	$ 400		$ 600
2000 Stock Plan
Stock-based compensation
Number of shares of common stock available for future grant	0		0