Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001274644 (http://www.sec.gov/CIK)

Debt Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Debt Disclosure [Abstract]
Schedule of maturities	Future payments under the Loan Agreement as of December 31, 2016 are as follows (in thousands): Years Ending December 31:   2017 $ 3,839 2018 4,442 2019 3,261 Total future minimum payments 11,542 Less amount representing interest 1,542 Notes payable, gross 10,000 Unamortized discount on notes payable (297 ) Notes payable 9,703
Schedule of Outstanding Convertible Preferred and Common Stock Warrants and Corresponding Exercise Price	The following table summarizes the outstanding common stock warrants and the corresponding exercise price as of December 31, 2016 and 2015:     Number of Warrants Outstanding  at December 31   Per Share Exercise     Issuance Date   2016   2015   Price   Expiration 9/30/2010   3,240   3,240   $ 160.44   9/30/2017 1/31/2012   13,623   13,623   44.04   1/31/2022 3/30/2012   13,256   24,388   0.67   3/30/2019 6/30/2012   36,583   36,583   0.67   6/30/2019 10/1/2012   51,425   62,558   0.67   10/1/2019 11/8/2013   788,177   788,177   7.66   11/8/2018 7/30/2015   97,680   97,680   $ 4.10   7/30/2025 Total outstanding common stock warrants   1,003,984   1,026,249