Consolidated Balance Sheets - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 30,915,374	$ 62,944,044
Marketable securities	174,688,468	48,302,507
Accounts receivable	0	95,285
Prepaid expenses and other current assets	3,789,732	760,872
Total current assets	209,393,574	112,102,708
Property and equipment, net	11,663,559	7,442,477
Long-term investments	4,725,041	7,357,423
Other assets		155,904
Restricted cash	480,000	80,000
Total assets	226,262,174	127,138,512
Current liabilities:
Accounts payable	2,160,869	3,692,414
Accrued expenses and other current liabilities	6,245,233	4,366,560
Current portion of long-term debt	9,133,991
Total current liabilities	17,540,093	8,058,974
Long-term debt	21,398,792	15,002,039
Other long-term liabilities	291,333	91,055
Total liabilities	39,230,218	23,152,068
Commitments and contingencies
Preferred Stock, $0.001 par value; 10,000,000 shares authorized at December 31, 2016 and December 31, 2015 and 0 shares issued and outstanding at December 31, 2016 and December 31, 2015
Stockholders’ equity:
Common stock, $0.001 par value; 100,000,000 shares authorized; 31,667,469 and 21,570,395 shares issued and outstanding, at December 31, 2016 and December 31, 2015, respectively	31,667	21,570
Additional paid-in capital	398,757,135	243,853,799
Accumulated other comprehensive income	(70,613)	(96,651)
Accumulated deficit	(211,686,233)	(139,792,274)
Total stockholders’ equity	187,031,956	103,986,444
Total liabilities and stockholders’ equity	$ 226,262,174	$ 127,138,512