Restructuring Charges Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Percentage workforce reduction										20.00%
Restructuring charges		$ (43)	$ 216	$ 49	$ 1,190	$ 4,581	$ (21)	$ (31)	$ 424	$ 1,412	$ 4,953	$ 3,514
2016 Restructuring Plan
Percentage workforce reduction	20.00%
Employee termination costs | 2016 Restructuring Plan
Restructuring charges										$ 1,200