Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregated revenue	$ 17,607	$ 9,634
Product revenue
Disaggregated revenue	0	2,300
License and royalty revenue
Disaggregated revenue	10,011	350
Contract Revenue
Disaggregated revenue	7,596	6,984
Transferred at Point in Time
Disaggregated revenue	10,200	4,266
Transferred at Point in Time | Product revenue
Disaggregated revenue	0	2,300
Transferred at Point in Time | License and royalty revenue
Disaggregated revenue	10,011	350
Transferred at Point in Time | Contract Revenue
Disaggregated revenue	189	1,616
Transferred over Time
Disaggregated revenue	7,407	5,368
Transferred over Time | Product revenue
Disaggregated revenue	0	0
Transferred over Time | License and royalty revenue
Disaggregated revenue	0	0
Transferred over Time | Contract Revenue
Disaggregated revenue	$ 7,407	$ 5,368