Consolidated Balance Sheets - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Current assets:    
Cash and cash equivalents $ 21,464 $ 14,920
Restricted cash 361 361
Marketable securities 11,577 5,274
Prepaid expenses and other current assets 451 184
Total current assets 33,853 20,739
Property, equipment and leasehold improvements, net 510 938
Other assets 421 115
Total assets 34,784 21,792
Current liabilities:    
Accounts payable 1,011 521
Loan payable, current portion 423 395
Derivative warrant liability 1,314 1,907
Deferred rent, current portion 141 115
Accrued expenses 1,959 374
Total current liabilities 4,848 3,312
Loan payable, net of current portion 852 1,275
Deferred rent, net of current portion 135 276
Total liabilities 5,835 4,863
Commitments and contingencies
Stockholders' equity:    
Common stock, $0.00001 par value, authorized 100,000,000 shares, issued and outstanding 32,044,087 shares at December 31, 2016; and authorized 50,000,000 shares, issued and outstanding 27,555,948 shares at December 31, 2015 1 1
Additional paid-in capital 185,955 150,497
Accumulated deficit (157,007) (133,569)
Total stockholders' equity 28,949 16,929
Total liabilities and stockholders' equity $ 34,784 $ 21,792