Liquidity and Capital Resources (Details) - USD ($)		1 Months Ended	6 Months Ended		12 Months Ended
	Mar. 16, 2020	Feb. 29, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Liquidity and Capital Resources
Cash and cash equivalents			$ 26,697,063		$ 11,794,526
Investments available-for-sale			13,258,197		14,250,176
Working capital net			40,000,000.0
Accumulated deficit			(321,392,548)		(306,516,265)
Net cash used in operating activities			$ (16,154,287)	$ (15,778,417)
Common shares sold (in shares)		3,670,212	987,716
Proceeds from the issuance of common shares		$ 8,000,000.0	$ 2,034,073		$ 5,383,079
Net draw down proceeds	$ 21,200,000
Remaining amount available for sale			$ 32,600,000