Discontinued Operations - Summary of Financial Data for Equity Method Investments Included in Discontinued Operations (Details) - TS Biotechnology Holdings LLC and Enviro Flight LLC - Discontinued Operations, Held-for-sale - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Current assets	$ 703	$ 5,119
Noncurrent assets	30,549	29,326
Total assets	31,252	34,445
Current liabilities	2,352	1,005
Non-current liabilities	88	0
Total liabilities	2,440	1,005
Net assets	28,812	33,440
Revenues	510	268	$ 254
Operating expenses	9,159	12,709	10,671
Operating loss	(8,649)	(12,441)	(10,417)
Other, net	21	39	(8)
Net loss	$ (8,628)	$ (12,402)	$ (10,425)