Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2015

Accounting Policies [Abstract]

Schedule of assets and liabilities that are measured at fair value on a recurring basis

The following table summarizes the assets and liabilities measured at fair value on a recurring basis (in thousands):

	June 30, 2015		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	3,676	$	3,676	$	—	$	—
Money market funds	7,923		7,923		—		—
Corporate debt securities	1,780		—		1,780		—
Total cash and cash equivalents	13,379		11,599		1,780		—
Short-term investments:
Corporate debt securities	36,999		—		36,999		—
Commercial paper	8,499		—		8,499		—
Total short-term investments	45,498		—		45,498		—
Total	$	58,877	$	11,599	$	47,278	$	—

	December 31, 2014		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	1,025	$	1,025	$	—	$	—
Money market funds	3,565		3,565		—		—
Corporate debt securities	2,003		—		2,003		—
Total cash and cash equivalents	6,593		4,590		2,003		—
Short-term investments:
Corporate debt securities	21,210		—		21,210		—
Commercial paper	1,500		—		1,500		—
Total short-term investments	22,710		—		22,710		—
Total	$	29,303	$	4,590	$	24,713	$	—

Schedule of potentially dilutive securities not included in the calculation of diluted net loss per share because to do so would be anti-dilutive

The following table presents the weighted average number of potentially dilutive securities not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities:

	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2015	2014	2015	2014
Common stock options	554,689	272,538	470,934	281,955
Common stock warrants	1,792,069	1,558,801	1,765,511	1,606,067
Total	2,346,758	1,831,339	2,236,445	1,888,022