Share-based Compensation - Expense and Assumptions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation recognized	$ 2,089	$ 2,212	$ 6,338	$ 6,669
Product, technology, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation recognized	2,067	2,166	6,259	6,508
Cost of goods sold
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation recognized	$ 22	$ 46	$ 79	$ 161