Leases - (Details) ¥ in Millions	1 Months Ended		6 Months Ended
	Nov. 30, 2019 USD ($) m²	Nov. 30, 2019 CNY (¥) m²	Jun. 30, 2021 USD ($) lease	Jun. 30, 2020 USD ($)
Number of Operating Leases | lease			7
Weighted average remaining lease term			34 years 3 months 21 days
Weighted average discount rates			3.60%
Number of expired leases | lease			2
Number of expired leases renewed | lease			1
Rent expenses | $			$ 789,000	$ 749,000
Variable lease costs | $			0	0
Sublease income | $			$ 0	$ 0
CASI Wuxi
Term of lease contract	50 years	50 years
Land parcel area (in square meters) | m²	74,028.40	74,028.40
Prepaid lease payments for the land use right	$ 6,500,000	¥ 45