Condensed Consolidated Balance Sheets - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 29,156,521	$ 55,061,329
Short-term investment securities	31,445,616	22,166,512
Interest receivable	108,458	186,021
Prepaid research and development	10,121,215	9,151,142
Other current assets	500,564	308,327
Total current assets	71,332,374	86,873,331
Restricted cash	582,184	579,143
Long-term investment securities	0	25,003,032
Leasehold interest	2,517,771	0
Equipment, net	327,674	47,122
Goodwill	799,391	799,391
Other assets	127,700	171,182
Total assets	75,687,094	113,473,201
Current liabilities:
Accounts payable and accrued expenses	15,550,129	9,346,068
Accrued compensation	1,061,626	818,472
Current portion of deferred revenue	152,381	152,381
Notes payable	117,126	211,549
Total current liabilities	16,881,262	10,528,470
Deferred rent	793,968	0
Deferred revenue, net of current portion	1,257,143	1,371,429
Total liabilities	18,932,373	11,899,899
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value per share (10,000,000 shares authorized, none issued and outstanding as of September 30, 2016 and December 31, 2015)	0	0
Common stock, $0.001 par value per share (150,000,000 shares authorized, 54,765,890 and 54,095,110 shares issued, 54,724,581 and 54,053,801 shares outstanding at September 30, 2016 and December 31, 2015, respectively)	54,766	54,095
Contingently issuable shares	6	6
Additional paid-in capital	269,646,963	259,887,464
Treasury stock, at cost, 41,309 shares at September 30, 2016 and December 31, 2015	(234,337)	(234,337)
Accumulated deficit	(212,712,677)	(158,133,926)
Total stockholders’ equity	56,754,721	101,573,302
Total liabilities and stockholders’ equity	$ 75,687,094	$ 113,473,201