Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2015

Computation of Basic and Diluted Net Loss per Share

The following table sets forth the reconciliation of the numerator and denominator used in the computation of basic and diluted net loss per share for the three and six months ended June 30, 2015 and 2014 (in thousands, except per share amounts):


	Three Months Ended June 30,						Six Months Ended June 30,
	2015			2014			2015			2014
Numerator for Basic and Diluted:
Net loss used for basic calculation	$	(15,972	)	$	(7,589	)	$	(25,432	)	$	(7,814	)
Effect of revaluation of warrant liability		—			(4,007	)		(3,589	)		(13,041	)

Adjusted net loss used for diluted calculation	$	(15,972	)	$	(11,596	)	$	(29,021	)	$	(20,855	)

Denominator:
Basic weighted average number of shares outstanding		95,728			72,899			94,576			72,495
Effect of dilutive potential shares		—			1,618			1,106			2,432

Diluted weighted average number of shares outstanding		95,728			74,517			95,682			74,927

Net loss per share:
Basic	$	(0.17	)	$	(0.10	)	$	(0.27	)	$	(0.11	)
Diluted	$	(0.17	)	$	(0.16	)	$	(0.30	)	$	(0.28	)

Anti-Dilutive Effect of Common Shares

The table below presents shares underlying stock options, employee stock purchase plan rights, and warrants that are excluded from the calculation of the weighted average number of shares outstanding used for the calculation of diluted net loss per share. These are excluded from the calculation due to their anti-dilutive effect for the three and six months ended June 30, 2015 and 2014 (shares in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Weighted average number of anti-dilutive potential shares:
Stock options		6,910		12,160		5,793		11,587
Warrants		2,985		—		—		—

Total		9,895		12,160		5,793		11,587