Company Operations by Product, Customer and Geographic Area - Data by Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue by Geographic Region:
Total revenues	$ 22,334	$ 59,215	$ 103,269
Long-lived Assets by Geographic Region:
Long-lived assets	26,482	29,694	35,154
U.S.
Revenue by Geographic Region:
Total revenues	22,334	59,215	101,423
Long-lived Assets by Geographic Region:
Long-lived assets	20,424	22,254	27,761
France
Long-lived Assets by Geographic Region:
Long-lived assets	11	196	1,365
Ireland
Revenue by Geographic Region:
Total revenues	0	0	1,846
Long-lived Assets by Geographic Region:
Long-lived assets	$ 6,047	$ 7,244	$ 6,028