Revenue Recognition - Revenue by Timing of Transfer of Goods or Services (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 4,419	$ 3,518
Goods or services transferred at a point in time
Disaggregation of Revenue [Line Items]
Total revenue	2,408	1,952
Goods or services transferred over time
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,011	$ 1,566