Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2014

Derivative Financial Instruments

Schedule of changes in derivative financial instruments and associated liability balance

Date	Description	Warrants		Derivative Instrument Liability (in thousands)
12/31/2011	Balance of derivative financial instruments liability	2,265,160		$	3,325
3/31/2012	Fair value of new warrants issued during the quarter	—		—
3/31/2012	Change in fair value of warrants during the quarter	—		(8		)
6/30/2012	Warrants classified to derivative liability during quarter	112,500		169
6/30/2012	Change in fair value of warrants during the quarter	—		1,317
9/30/2012	Fair value of new warrants issued during the quarter	—		—
9/30/2012	Change in fair value of warrants during the quarter	—		(140		)
12/31/2012	Fair value of new warrants issued during the quarter	—		—
12/31/2012	Change in fair value of warrants during the quarter	—		764
12/31/2012	Reclassification of derivative liability to equity during the quarter	(112,500	)	(169		)
12/31/2012	Balance of derivative financial instruments liability	2,265,160		5,258
3/31/2013	Change in fair value of warrants during the quarter	—		1,093
3/31/2013	Balance of derivative financial instruments liability	2,265,160		6,351
6/30/2013	Fair value of new warrants issued during the quarter	—		—
6/30/2013	Reclassification of derivative liability to equity during the quarter	(1,406,691	)	(3,575		)
6/30/2013	Change in fair value of warrants during the quarter	—		(1,803		)
9/30/2013	Fair value of new warrants issued during the quarter	—		—
9/30/2013	Change in fair value of warrants during the quarter	—		77
12/31/2013	Fair value of new warrants issued during the quarter	—		—
12/31/2013	Change in fair value of warrants during the quarter	—		484
12/31/2013	Balance of derivative financial instruments liability	858,469		1,534
3/31/2014	Fair value of new warrants issued during the quarter	—		—
3/31/2014	Change in fair value of warrants during the quarter	—		(223		)
6/30/2014	Fair value of new warrants issued during the quarter	—		—
6/30/2014	Change in fair value of warrants during the quarter	—		(756		)
9/30/2014	Fair value of new warrants issued during the quarter	—		—
9/30/2014	Change in fair value of warrants during the quarter	—		(425		)
12/30/2014	Fair value of new warrants issued during the quarter	—		—
12/30/2014	Change in fair value of warrants during the quarter	—		42
12/30/2014	Balance of derivative financial instruments liability	858,469		$	172

Derivative instrument liability | Warrants | Black-Scholes option pricing model

Derivative Financial Instruments

Schedule of range of assumptions used to determine the fair value of the warrants

	Year ended December 31, 2014	Year ended December 31, 2013
Fair value of Synergy common stock	$3.05	$5.55
Expected warrant term	0.49-3.9 years	1.8-4.4 years
Risk-free interest rate	0.08%-1.32%	0.26%-1.76%
Expected volatility	52%-60%	60%
Dividend yield	0%	0%

Derivative instrument liability | Warrants | Binomial model

Derivative Financial Instruments

Schedule of range of assumptions used to determine the fair value of the warrants

	Year ended December 31, 2012
Estimated fair value of Synergy common stock	$3.28-$4.53
Expected warrant term	4.13-4.63 years
Risk-free interest rate	0.62%-1.04%
Expected volatility	60%
Dividend yield	0%