Redeemable Noncontrolling Interest - Changes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Redeemable Noncontrolling Interest
Balance at beginning of period	$ 21,074	$ 20,237	$ 20,670
Cash contribution by Wuxi LP	0	0	0	$ 20,000
Share of CASI Wuxi (net loss)/income	(309)	(23)	(584)	53
Accretion of redeemable noncontrolling interest	506	245	1,185	406
Balance at end of period	$ 21,271	$ 20,459	$ 21,271	$ 20,459