Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 10,264	$ 29,096
Short-term investments	6,800	3,402
Restricted cash	19,468	33,794
Deposits		133
Accounts receivable	31	492
Prepaid and other current assets	958	1,781
Total current assets	37,521	68,698
Restricted cash, noncurrent	125	125
Property and equipment, net	444	698
Total assets	38,090	69,521
Current liabilities:
Accounts payable	837	939
Accrued compensation	596	926
Other accrued liabilities	805	535
Deferred revenue, current portion	283	438
Deferred rent, current portion	41	19
Redeemable convertible notes	19,403	33,743
Derivative liability		1,156
Total current liabilities	21,965	37,756
Deferred revenue, noncurrent portion	47	292
Deferred rent, noncurrent portion	7	48
Total liabilities	22,019	38,096
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares and no shares authorized and outstanding at both December 31, 2016 and December 31, 2015
Common stock, $0.001 par value, 100,000,000 shares authorized; 801,756 and 762,005 shares issued and outstanding at December 31, 2016 and December 31, 2015	1	1
Additional paid-in capital	164,053	162,460
Accumulated other comprehensive income (loss)	(1)	1
Accumulated deficit	(147,982)	(131,037)
Total stockholders’ equity	16,071	31,425
Total liabilities and stockholders’ equity	$ 38,090	$ 69,521