Restructuring Charges - Schedule of Accrued Liabilities for Severance and Related Expenses and Payments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost And Reserve [Line Items]
Charge	$ 1,120	$ 1,351	$ 1,120
Severance and related expenses
Restructuring Cost And Reserve [Line Items]
Charge		1,351
Cash Payments		(1,322)
Ending balance		$ 29