CONDENSED BALANCE SHEETS - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 64,928,530	$ 31,228,192
Short-term investments	53,466,599	106,979,224
Receivables	8,076	55,074
Prepaid expenses	784,971	1,737,308
Other assets	129,535	255,912
Total current assets	119,317,711	140,255,710
Property and equipment, net	2,615,392	3,205,077
Other noncurrent assets	7,067	33,567
Total assets	121,940,170	143,494,354
Current liabilities:
Accounts payable	1,235,016	1,381,545
Accrued wages and benefits	1,521,264	2,705,475
Accrued clinical trial expenses	1,792,635	861,293
Accrued expenses and other liabilities	690,234	613,861
Total current liabilities	5,239,149	5,562,174
Other liabilities, net of current portion		2,873
Deferred revenue, net of current portion	756,944	781,944
Total liabilities	5,996,093	6,346,991
Stockholders’ equity:
Common stock: $0.001 par value, 100,000,000 shares authorized; 42,377,522 and 42,470,874 shares issued and outstanding at December 31, 2016 and March 31, 2017	42,575	42,378
Additional paid-in capital	393,060,063	390,768,742
Accumulated other comprehensive (loss) income	(34,863)	(41,196)
Retained deficit	(277,123,698)	(253,622,561)
Total stockholders’ equity	115,944,077	137,147,363
Total liabilities and stockholders’ equity	$ 121,940,170	$ 143,494,354