Restructuring Costs - Summary of Activity and Estimated Timing of Future Payouts for Accrued Restructuring Costs (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 661
Restructuring costs	253	$ 1,629
Non-cash asset impairment charge		(375)
Cash payments	(442)	(782)
Ending Balance	472	472
Estimated timing of future payments:
Remainder of 2019	310	310
2020	162	162
Total stock-based compensation expense	$ 472	$ 472