Notes Payable (Details)			1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 02, 2016 USD ($) shares	Jun. 23, 2014 USD ($)	Mar. 31, 2015 USD ($) shares	Sep. 30, 2016 USD ($) item $ / shares	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) item $ / shares	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Notes payable
Denominator used in calculation of daily measurement value | item				60		60
Convertible notes payable, discount				$ 12,940,871		$ 12,940,871		$ 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				30,809,129		30,809,129		$ 28,278,875
Interest expense incurred
Interest expense on debt				875,000	$ 875,000	2,625,000	2,613,445
Amortization of debt discount to interest expense				797,312	644,788	2,270,411	1,864,549
Amortization of deferred financing costs				86,614	86,614	259,843	264,737
Total interest expense				1,758,926	1,606,402	5,155,254	$ 4,742,731
8.00% Convertible Notes Due 2019
Notes payable
Aggregate principal amount		$ 47,000,000
Interest rate (as a percent)		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		952,760		952,760
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			500,000
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)		(952,760)		(952,760)
Cumulative amortization of debt discount				5,902,952		5,902,952
Carrying value				30,809,129		30,809,129
8.00% Convertible 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 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 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 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 Notes Due 2019 | Occurrence of fundamental changes
Notes payable
Redemption price as percentage of principal amount						100.00%
8.00% Convertible 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%
Medivir | 8.00% Convertible Notes Due 2019
Notes payable
Interest rate (as a percent)	8.00%
Debt outstanding	$ 41,550,000
Conversion of debt, initial conversion ratio						1
Stock issued upon conversion (in shares) | shares	12,222,222
Conversion of convertible notes to common stock	$ 2,200,000
Debt holders (as a percent)	100.00%
Debt repurchased	$ 12,000,000