Income Taxes (Tables)

12 Months Ended

Dec. 31, 2014

Income Taxes

Schedule of significant components of deferred tax assets

	December 31,
	2014		2013
Deferred tax assets:
Net operating losses	$	37,715	$	53,099
Research & other credits		1,527		2,227
Other		2,172		1,447
Total deferred tax assets		41,414		56,773
Valuation allowance		(41,414)		(56,773)
Net deferred tax assets	$	—	$	—

Schedule of reconciliation of the statutory tax rates and the effective tax rates

	Year Ended December 31,
	2014		2013		2012
Statutory rate	34	%	34	%	34	%
Valuation Allowance	(33.3)	%	(33.8)	%	(33)	%
Nondeductible Stock Compensation	(0.7)	%	(0.2)	%	(0.6)	%
Effective tax rate	—	%	—	%	—	%

Reconciliation of Beginning And Ending Amount Of Unrecognized Tax Benefits

Beginning at January 1, 2012		1,025
Additions based on tax positions related to prior year		39
Additions based on tax positions related to current year		5
Balance at December 31, 2012		1,069
Additions based on tax positions related to prior year		18
Additions based on tax positions related to current year		109
Balance at December 31, 2013		1,196
Additions based on tax positions related to current year		297
Balance at December 31, 2014	$	1,493