Consolidated Statements of Stockholders' Equity - 9 months ended Sep. 30, 2016 - USD ($) $ in Thousands	Total	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at at Dec. 31, 2015	$ 364,157
Balance at (in shares) at Dec. 31, 2015	64,077,140
Stock-based compensation plans
Total comprehensive income (loss)	$ 28,475	$ 21,956	$ 6,519
Balance at at Sep. 30, 2016	$ 323,161
Balance at (in shares) at Sep. 30, 2016	59,598,299