Stock-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	$ 5,019	$ 3,181	$ 9,615	$ 6,065
Selling, general and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	3,675	2,531	7,326	4,784
Research and development [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total share-based compensation	$ 1,344	$ 650	$ 2,289	$ 1,281