Deferred Revenue (Details) - USD ($)		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 14, 2020	Oct. 31, 2014	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2016	Dec. 31, 2019
Deferred Revenue Arrangement [Line Items]
Deferred revenue			$ 11,084,000		$ 11,084,000			$ 12,076,000
Baxter Healthcare Organization
Deferred Revenue Arrangement [Line Items]
Upfront payment		$ 20,000,000
Recognized deferred revenue			500,000	$ 1,000,000.0	500,000	$ 100,000
Deferred revenue			8,200,000		$ 8,200,000			9,100,000
Refund eligible for, percent of upfront fee					25.00%
Partial refund					$ 5,000,000.0
Wanbang Biopharmaceutical
Deferred Revenue Arrangement [Line Items]
Upfront payment							$ 4,000,000.0
Recognized deferred revenue			53,000	$ 100,000	53,000	$ 100,000
Deferred revenue			2,900,000		2,900,000			$ 3,000,000.0
Sun Pharma Agreements
Deferred Revenue Arrangement [Line Items]
Upfront payment	$ 100,000
Recognized deferred revenue			$ 2,500		$ 5,000