Notes Payable (Details) $ / shares in Units, shares in Millions		1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 23, 2014 USD ($)	Mar. 31, 2015 USD ($) shares	Jun. 30, 2016 USD ($) item $ / shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) item $ / shares	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Notes payable
Denominator used in calculation of daily measurement value | item			60		60
Convertible notes payable, discount			$ 12,785,423		$ 12,785,423		$ 15,471,125
Conversion of convertible notes to common stock						$ 2,080,292
Converted debt cash payment						825,001
Debt exchange expense						818,541
Details of Notes reflected in balance sheet
Carrying value			29,925,203		29,925,203		$ 28,278,875
Interest expense incurred
Interest expense on debt			875,000	$ 875,000	1,750,000	1,738,445
Amortization of debt discount to interest expense			756,093	611,455	1,473,099	1,219,761
Amortization of deferred financing costs			86,614	86,615	173,229	178,123
Total interest expense			$ 1,717,707	1,573,070	$ 3,396,328	$ 3,136,329
8.00% Convertible Senior Notes Due 2019
Notes payable
Aggregate principal amount	$ 47,000,000
Interest rate (as a percent)	8.00%		8.00%		8.00%
Debt outstanding			$ 43,750,000		$ 43,750,000
Conversion of debt, initial conversion ratio					148.3019
Principal amount of notes, basis for conversion			$ 1,000		$ 1,000
Initial conversion price per share of common stock (in dollars per share) | $ / shares			$ 6.74		$ 6.74
Multiplier used in calculation of daily conversion values | item			0.0167		0.0167
Period from conversion date considered for interest make-whole payment	3 years
Liability component	$ 30,800,000
Carrying value of notes	27,700,000
Value of the embedded interest make-whole derivative	3,100,000
Equity component of convertible notes on issuance date	16,200,000		$ 15,002,020		$ 15,002,020
Transaction costs	2,900,000
Transaction costs allocated to equity	1,000,000
Capitalized deferred financing costs	1,900,000		1,039,374		1,039,374
Conversion of convertible notes to common stock		$ 3,250,000
Converted debt cash payment		$ 800,000
Stock issued upon conversion of notes (in shares) | shares		0.5
Debt exchange expense				$ 800,000
Details of Notes reflected in balance sheet
Conversion option reported in equity	(16,200,000)		(15,002,020)		(15,002,020)
Interest make-whole derivative			(2,889,043)		(2,889,043)
Unamortized debt issuance costs	$ (1,900,000)		(1,039,374)		(1,039,374)
Cumulative amortization of debt discount			5,105,640		5,105,640
Carrying value			29,925,203		29,925,203
8.00% Convertible Senior Notes Due 2019 | Conversion of notes any time prior to the close of business immediately preceding February 15, 2019
Notes payable
Principal amount of notes, basis for conversion			$ 1,000		$ 1,000
Threshold trading days (whether or not consecutive) | item					20
Consecutive trading day period					30 days
Threshold percentage of common stock price to determine eligibility of conversion					100.00%
Threshold trading days during which principal amount of notes for such trading day was less than 98% of the product of the last reported sale price of common stock | item					5
Consecutive trading day period prior to specified trading days during which principal amount of notes for such trading day was less than 98% of the product of the last reported sale price of common stock					10 days
Maximum ratio of trading price for each trading day in measurement period to last reported sales price of entity's stock on each trading day of measurement period			98.00%		98.00%
8.00% Convertible Senior Notes Due 2019 | Conversion of notes after obtaining stockholder approval | Physical settlement
Notes payable
Principal amount of notes, basis for conversion			$ 1,000		$ 1,000
8.00% Convertible Senior Notes Due 2019 | Conversion of notes after obtaining stockholder approval | Cash settlement
Notes payable
Principal amount of notes, basis for conversion			1,000		$ 1,000
Consecutive trading days during the related observation period considered in calculation of daily conversion values					60 days
8.00% Convertible Senior Notes Due 2019 | Conversion of notes after obtaining stockholder approval | Combination settlement
Notes payable
Principal amount of notes, basis for conversion			$ 1,000		$ 1,000
Consecutive trading days during the related observation period considered in calculation of daily conversion values					60 days
8.00% Convertible Senior Notes Due 2019 | Occurrence of fundamental changes
Notes payable
Redemption price as percentage of principal amount required by holders upon occurrence of certain fundamental changes					100.00%
8.00% Convertible Senior Notes Due 2019 | Conversion of notes on or after December 31, 2014 with interest make-whole payment
Notes payable
Threshold trading days (whether or not consecutive) | item					20
Consecutive trading day period					30 days
Number of trading days prior to a conversion date within which threshold trading days should complete | item					5
Discount rate used for calculation of interest make-whole payment (as a percent)					2.00%
Period from conversion date considered for interest make-whole payment					3 years
Number of trading days immediately preceding the conversion date used to determine daily value weighted average price | item					10
Stock value as percentage of simple average of the daily value-weighted average price of common stock for a specified trading days			92.50%		92.50%