Consolidated Balance Sheets - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
CURRENT ASSETS:    
Cash and cash equivalents $ 56,058 $ 26,067
Held-to-maturity investments 38,551 70,055
Prepaid expenses and other current assets 1,532 1,194
Total current assets 96,141 97,316
NONCURRENT ASSETS:    
Property and equipment-net 2,684 2,165
Held-to-maturity investments   2,501
Assets held in restriction 1,116 1,380
Other noncurrent assets 82 243
Total noncurrent assets 3,882 6,289
TOTAL ASSETS 100,023 103,605
CURRENT LIABILITIES:    
Accounts payable 2,621 1,237
Accrued expenses and other current liabilities 6,376 3,845
Deferred rent 4 77
Total current liabilities 9,001 5,159
NONCURRENT LIABILITIES:    
Security deposit   106
Total noncurrent liabilities   106
TOTAL LIABILITIES $ 9,001 $ 5,265
COMMITMENTS AND CONTINGENCIES (Note 15)
STOCKHOLDERS' EQUITY:    
Preferred stock, $0.0001 par value-5,000,000 shares authorized; no shares issued and outstanding at December 31, 2015 and December 31, 2014, respectively
Common stock, $0.0001 par value-150,000,000 shares authorized; 20,594,575 and 17,786,867 shares issued and outstanding at December 31, 2015 and 2014, respectively $ 2 $ 3
Additional paid-in capital 287,263 231,741
Accumulated deficit (196,243) (133,404)
Total stockholders' equity 91,022 98,340
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY $ 100,023 $ 103,605