CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 34,732,782	$ 15,431,622
Short-term investments	111,983,789	158,168,832
Receivables	20,000	8,678
Prepaid expenses	1,492,376	772,579
Other assets	311,607	493,863
Total current assets	148,540,554	174,875,574
Property and equipment, net	3,396,163	3,398,398
Other noncurrent assets	49,428	111,605
Total assets	151,986,145	178,385,577
Current liabilities:
Accounts payable	1,516,856	1,262,565
Accrued wages and benefits	1,701,378	3,272,237
Accrued clinical trial expenses	902,294	804,066
Accrued expenses and other liabilities	430,668	850,125
Total current liabilities	4,551,196	6,188,993
Other liabilities, net of current portion	7,178	18,503
Deferred revenue, net of current portion	794,444	831,944
Total liabilities	5,352,818	7,039,440
Stockholders’ equity:
Common stock: $0.001 par value, 100,000,000 shares authorized; 42,034,733 and 42,268,069 shares issued and outstanding at December 31, 2015 and September 30, 2016	42,268	42,035
Additional paid-in capital	389,117,203	381,118,489
Accumulated other comprehensive (loss) income	31,640	(79,399)
Retained deficit	(242,557,784)	(209,734,988)
Total stockholders’ equity	146,633,327	171,346,137
Total liabilities and stockholders’ equity	$ 151,986,145	$ 178,385,577