Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash	$ 539	$ 239
Money market funds	10,336	15,721
Accounts receivable, net	274	1,501
Inventories, net	3,416	8,209
Prepaid expenses and other current assets	717	1,094
Total current assets	15,282	26,764
Property and equipment, net	1,489	1,432
Deposits and other assets	39	49
Total assets	16,810	28,245
Current liabilities:
Accounts payable	1,156	710
Accrued expenses	2,088	2,068
Accrued compensation expense	1,600	2,069
Accrued clinical trial expense	629	616
Deferred revenue	85	322
Deferred grant revenue	104	2,197
Total current liabilities	5,662	7,982
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: 42,701 and 35,942 at December 31, 2016 and December 31, 2015, respectively	186,769	166,049
Common stock to be issued	153	205
Additional paid-in capital	30,697	27,277
Notes receivable to finance stock option exercises	(2)	(5)
Accumulated other comprehensive loss	(608)	(581)
Accumulated deficit	(205,861)	(172,682)
Total stockholders' equity	11,148	20,263
Total liabilities and stockholders' equity	$ 16,810	$ 28,245