Related Party Transactions - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2020	Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Shares issued as payment for services						$ 7,987
Proceeds from sales of equity securities					$ 0	589
Other receivables		$ 4,978	$ 285		285		$ 4,978
Third Security, LLC
Related Party Transaction [Line Items]
Expense for services			56	$ 8	132	$ 26
Common stock calculation period							30 days
Shares issued as payment for services (in shares)				340,453		1,180,446
Shares issued as payment for services				$ 1,855		$ 6,217
Sublease rental income			$ 18	$ 22	$ 64	$ 66
Third Security, LLC | Common Stock
Related Party Transaction [Line Items]
Expense for services							$ 800
Castle Creek Biosciences, Inc.
Related Party Transaction [Line Items]
Proceeds from sales of equity securities		1,280
Proceeds from convertible notes receivable and investment in preferred stock	$ 3,311
Other receivables		$ 3,311					$ 3,311
Third Security, LLC | Executive Chairman
Related Party Transaction [Line Items]
Ownership interest			100.00%		100.00%