BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 12,810	$ 21,248
Restricted cash	268	267
Marketable securities	102,035	92,524
Interest and other receivables	475	1,206
Prepaid assets	524	647
Total current assets	116,112	115,892
Noncurrent marketable securities	13,954	32,661
Property and equipment, net	183	207
Total assets	130,249	148,760
Current liabilities:
Accounts payable	225	160
Accrued compensation and benefits	2,843	3,026
Accrued collaboration charges	3,367	2,328
Accrued liabilities	1,434	1,120
Total current liabilities	7,869	6,634
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 3,000,000 shares authorized; no shares issued and outstanding at December 31, 2016 and 2015
Common Stock, $0.001 par value; 300,000,000 shares authorized; 159,158,636 and 158,781,359 shares issued and outstanding at December 31, 2016 and 2015, respectively	159	159
Additional paid-in capital	1,080,198	1,070,567
Accumulated deficit	(957,924)	(928,387)
Accumulated other comprehensive loss	(53)	(213)
Total stockholders' equity	122,380	142,126
Total liabilities and stockholders' equity	$ 130,249	$ 148,760

Carrying value as of the balance sheet date of obligations incurred and payable to collaboration partner for which invoices have not yet been received under the respective collaboration agreement (due within one year or within the normal operating cycle if longer).

No definition available.