Fair Value of Financial Assets and Liabilities - Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2015

Derivatives And Fair Value [Line Items]

Financial Liabilities Measured at Fair Value

The following fair value hierarchy table presents information about each major category of the Company's financial liabilities measured at fair value on a recurring basis:

	Quoted Prices in
	Active Markets		Significant Other		Significant
	for Identical		Observable Inputs		Unobservable
	Items (Level 1)		(Level 2)		Inputs (Level 3)		Total
June 30, 2015
Liabilities
Preferred B stock derivative liability	$	-	$	-	$	10,032,000	$	10,032,000
Warrant liability		-		-		3,984,000		3,984,000
Total liabilities	$	-	$	-	$	14,016,000	$	14,016,000
December 31, 2014
Liabilities
Preferred B stock derivative liability	$	-	$	-	$	12,320,000	$	12,320,000
Warrant liability		-		-		5,826,000		5,826,000
Total liabilities	$	-	$	-	$	18,146,000	$	18,146,000

Changes in Fair Value of Derivative and Warrant Liability

The following table sets forth a summary of changes in the fair value of the Company's Series B redeemable convertible preferred stock derivative and warrant liability, which represents a recurring measurement that is classified within Level 3 of the fair value hierarchy, wherein fair value is estimated using significant unobservable inputs:

			Preferred B
	Warrant		Stock Derivative
	Liability		Liability
Balance, December 31, 2014	$	5,826,000	$	12,320,000
Issuances		4,210,000		-
Exercises		(676,000)		-
Conversions to common stock		-		(636,000)
Amount reclassified to additional paid in capital related to amendment of warrants		(5,462,000)		-
Changes in estimated fair value		86,000		(1,652,000)
Balance, June 30, 2015	$	3,984,000	$	10,032,000

Series B redeemable convertible preferred stock [Member]

Derivatives And Fair Value [Line Items]

Valuation Assumptions Used

The following assumptions were used at June 30, 2015 and December 31, 2014:

	June 30,			December 31,
	2015			2014
Volatility		112	%		91	%
Expected term (years)		0.75			1.25
Risk-free interest rate		0.2	%		0.36	%
Dividend yield		0	%		0	%
Exercise price	$	0.14		$	0.14
Common stock closing price	$	9.35		$	10.50

Warrant Liability [Member]

Derivatives And Fair Value [Line Items]

Valuation Assumptions Used

The following assumptions were used at June 30, 2015 and December 31, 2014:

	June 30, 2015						December 31, 2014
				March						June			July			December
	2011			2015			2011			2013			2013			2013
Volatility		96	%		144	%		155	%		155	%		155	%		151	%
Expected term (years)		1.48			4.72			1.98			3.49			3.54			3.98
Risk-free interest rate		0.45	%		1.55	%		0.67	%		1.23	%		1.25	%		1.37	%
Dividend yield		0	%		0	%		0	%		0	%		0	%		0	%
Exercise price	$	23.00		$	10.75		$	23.00		$	7.00		$	7.00		$	12.50
Common stock closing price	$	9.35		$	9.35		$	10.50		$	10.50		$	10.50		$	10.50