Performance-Based Common Stock Warrants Performance-Based Common Stock Warrants - (Details) - Common stock purchase warrant - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Class of Warrant or Right [Line Items]
Reduction to net sales	$ 331	$ 1,193	$ 1,263	$ 2,059
Income tax benefit	$ 123	$ 438	$ 471	$ 756