CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,183,460	$ 13,915,094
Short-term investments	18,619,712	23,978,022
Accounts receivable	80,348	100,460
Prepaid expenses and other assets	845,845	956,616
Total current assets	29,729,365	38,950,192
Property and equipment, net	3,567,064	3,826,915
Other assets	628,640	1,173,304
Total Assets	33,925,069	43,950,411
Current liabilities:
Accounts payable	968,385	1,130,536
Accrued expenses	3,830,741	4,021,365
Deferred rent	285,246	285,246
Current portion of long-term debt	3,873,438	2,360,109
Total current liabilities	8,957,810	7,797,256
Long-term debt, less current portion	12,699,739	14,176,359
Derivative financial instruments—warrants	279,434	834,940
Deferred rent, net of current portion	1,307,598	1,373,717
Total Liabilities	23,244,581	24,182,272
Commitments and contingencies (Note 9)
Stockholders’ equity
Preferred stock, $0.001 par value, 20,000,000 shares authorized; 60,600 shares outstanding at March 31, 2017 and December 31, 2016; designated as Series A Convertible Preferred Stock with liquidation preference of $606,000 at March 31, 2017 and December 31, 2016	60	60
Common stock, $0.0001 par value, 150,000,000 shares authorized; 30,967,791 and 30,696,791 shares issued and outstanding at March 31, 2017 and December 31, 2016, respectively	3,098	3,070
Additional paid-in capital	168,811,755	167,890,984
Accumulated other comprehensive loss	(13,626)	(10,773)
Accumulated deficit	(158,120,799)	(148,115,202)
Total stockholders’ equity	10,680,488	19,768,139
Total liabilities and stockholders’ equity	$ 33,925,069	$ 43,950,411