Casi Holdings and Evomela Supply Contract - Additional Information (Details) $ in Thousands, shares in Millions	2 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($) shares	Mar. 31, 2015 agreement	Jun. 30, 2020 USD ($) shares	Dec. 31, 2019 USD ($)
Other Commitments [Line Items]
Equity securities	$ 23,085		$ 23,085	$ 31,047
CASI out-license
Other Commitments [Line Items]
Number of agreements | agreement		3
Number of shares held in investment (shares) | shares			9.2
Percentage of ownership (less than)			10.00%
Equity securities	$ 23,100		$ 23,100
Sale of shares (shares) | shares	0.8
Gain on sale of shares	$ 500