Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 351,985,085	$ 176,267,666
Prepaid assets	19,802,008	24,333,851
Other current assets	1,307,591	1,837,704
Total current assets	373,094,684	202,439,221
Non-current Assets:
Right-of-use assets	14,110,209
Property and equipment, net	1,654,999	977,918
Other assets	385,088	116,420
Total assets	389,244,980	203,533,559
Current liabilities:
Accounts payable	8,360,527	10,254,938
Accrued expenses	54,782,951	5,103,002
Current portion of long-term-debt		1,666,667
Current portion of operating lease liabilities	2,609,341
Total current liabilities	65,752,819	17,024,607
Long-term liabilities:
Convertible Senior Notes	142,566,851
Development derivative liability	134,839,000
Term loan facility		18,722,321
Promissory note		6,655,193
Operating lease liabilities	11,856,634
Other liabilities		158,783
Total liabilities	355,015,304	42,560,904
Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized and zero shares issued and outstanding at December 31, 2018 and 2019	0	0
Common stock, $0.0001 par value; 200,000,000 shares authorized and at December 31, 2018 and 2019; 56,279,307 and 63,938,003 shares issued and outstanding at December 31, 2018 and 2019, respectively	6,393	5,628
Additional Paid-in capital	615,849,518	437,855,681
Accumulated other comprehensive loss	(153,775)	(122,807)
Accumulated deficit	(581,472,460)	(276,765,847)
Total stockholders' equity	34,229,676	160,972,655
Total liabilities and stockholders' equity	$ 389,244,980	$ 203,533,559