Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregated revenue	$ 1,190	$ 11,572	$ 4,281	$ 15,774
Product revenue
Disaggregated revenue	999	0	1,198	0
Royalty revenue
Disaggregated revenue	17	10,000	17	10,011
Contract revenue
Disaggregated revenue	174	1,572	3,066	5,763
Transferred at Point in Time
Disaggregated revenue	1,137	10,026	1,388	10,193
Transferred at Point in Time | Product revenue
Disaggregated revenue	999	0	1,198	0
Transferred at Point in Time | License and royalty revenue
Disaggregated revenue	17	10,000	17
Transferred at Point in Time | Royalty revenue
Disaggregated revenue				10,011
Transferred at Point in Time | Contract revenue
Disaggregated revenue	121	26	173	182
Transferred over Time
Disaggregated revenue	53	1,546	2,893	5,581
Transferred over Time | Product revenue
Disaggregated revenue	0	0	0	0
Transferred over Time | License and royalty revenue
Disaggregated revenue	0	0	0
Transferred over Time | Royalty revenue
Disaggregated revenue				0
Transferred over Time | Contract revenue
Disaggregated revenue	$ 53	$ 1,546	$ 2,893	$ 5,581