Condensed Consolidated Balance Sheets - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 28,577,832	$ 55,061,329
Short-term investment securities	25,680,319	22,166,512
Interest receivable	133,766	186,021
Prepaid research and development	14,510,025	9,151,142
Other current assets	649,738	308,327
Total current assets	69,551,680	86,873,331
Restricted cash	581,161	579,143
Long-term investment securities	21,435,015	25,003,032
Leasehold interest	1,968,734	0
Property, plant and equipment, net	333,859	47,122
Goodwill	799,391	799,391
Other assets	127,700	171,182
Total assets	94,797,540	113,473,201
Current liabilities:
Accounts payable and accrued expenses	13,080,176	9,346,068
Accrued compensation	796,376	818,472
Current portion of deferred revenue	152,381	152,381
Notes payable	90,564	211,549
Total current liabilities	14,119,497	10,528,470
Deferred rent	681,720	0
Deferred revenue, net of current portion	1,295,238	1,371,429
Total liabilities	16,096,455	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 June 30, 2016 and December 31, 2015)	0	0
Common stock, $0.001 par value per share (150,000,000 shares authorized, 54,497,932 and 54,095,110 shares issued, 54,456,623 and 54,053,801 shares outstanding at June 30, 2016 and December 31, 2015, respectively)	54,498	54,095
Contingently issuable shares	6	6
Additional paid-in capital	266,762,568	259,887,464
Treasury stock, at cost, 41,309 shares at June 30, 2016 and December 31, 2015	(234,337)	(234,337)
Accumulated deficit	(187,881,650)	(158,133,926)
Total stockholders’ equity	78,701,085	101,573,302
Total liabilities and stockholders’ equity	$ 94,797,540	$ 113,473,201