Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring cost incurred		$ 1,646	$ 2,100	$ 5,800
Reduction in workforce							7.00%
Restructuring Reserve [Roll Forward]
Accrued Charges at beginning of period	$ 4,346	4,686		0	$ 83	$ 337	$ 4,686
Cost incurred		1,646	2,100	5,800
Costs paid	(1,364)	(1,986)			(83)	(254)
Accrued Charges at end of period	2,982	4,346	4,686		0	83	2,982
Severance Charges
Restructuring Cost and Reserve [Line Items]
Restructuring cost incurred		1,646
Restructuring Reserve [Roll Forward]
Accrued Charges at beginning of period	3,556	3,896		0	83	337	3,896
Cost incurred		1,646
Costs paid	(1,364)	(1,986)			(83)	(254)
Accrued Charges at end of period	2,192	3,556	3,896		0	83	2,192
Other Associated Costs
Restructuring Cost and Reserve [Line Items]
Restructuring cost incurred		0
Restructuring Reserve [Roll Forward]
Accrued Charges at beginning of period	790	790		$ 0	0	0	790
Cost incurred		0
Costs paid	0	0			0	0
Accrued Charges at end of period	$ 790	$ 790	$ 790		$ 0	$ 0	$ 790