Casi Holdings and Evomela Supply Contract - Additional Information (Details) $ in Thousands, shares in Millions	1 Months Ended	6 Months Ended		12 Months Ended
	Apr. 30, 2019 USD ($) shares	Jun. 30, 2019 USD ($) shares	Jun. 30, 2018 USD ($)	Dec. 31, 2014 agreement	Dec. 31, 2018 USD ($)
Other Commitments [Line Items]
Equity securities		$ 32,153			$ 46,422
Gain (loss) on shares of common stock		$ 2,674	$ 0
CASI Out-License [Member]
Other Commitments [Line Items]
Number of agreements | agreement				3
Number of shares held in investment (shares) | shares		10.0
Percentage of ownership		10.50%
Equity securities		$ 32,200
Number of shares sold (shares) | shares	1.5
Gain (loss) on shares of common stock	$ 2,700