Restructuring - Summary of Restructuring Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost And Reserve [Line Items]
Balance at January 1, 2019	$ 30
Charges to expense	901	$ 119
Cash payments	(582)
Balance at June 30, 2019	349
Employee Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Balance at January 1, 2019	30
Charges to expense	901
Cash payments	(582)
Balance at June 30, 2019	$ 349