Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current assets:
Cash	$ 277	$ 239
Money market funds	17,546	15,721
Accounts receivable, net	447	1,501
Inventories, net	5,810	8,209
Prepaid expenses and other current assets	603	1,094
Total current assets	24,683	26,764
Property and equipment, net	1,527	1,432
Deposits and other assets	55	49
Total assets	26,265	28,245
Current liabilities:
Accounts payable	694	710
Accrued expenses	1,711	2,068
Accrued compensation expenses	2,055	2,069
Accrued clinical trial expenses	555	616
Deferred revenue	195	322
Deferred grant revenue	456	2,197
Total current liabilities	5,666	7,982
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value, 10,000 shares authorized; none outstanding
Common stock, no par value, 200,000 shares authorized; shares issued and outstanding: 42,247 and 35,942 at September 30, 2016 and December 31, 2015, respectively	186,618	166,049
Common stock to be issued	87	205
Additional paid-in capital	29,911	27,277
Notes receivable to finance stock option exercises	(2)	(5)
Accumulated other comprehensive loss	(524)	(581)
Accumulated deficit	(195,491)	(172,682)
Total stockholders' equity	20,599	20,263
Total liabilities and stockholders' equity	$ 26,265	$ 28,245