Subsequent Events - Additional Information (Detail)	Oct. 24, 2017 USD ($)	Oct. 23, 2017 USD ($) d $ / shares shares	Oct. 10, 2017 USD ($) $ / shares shares	Aug. 10, 2015 d $ / shares	Sep. 30, 2017 USD ($) shares	Jun. 29, 2017 $ / shares	Apr. 18, 2017 $ / shares	Dec. 31, 2016 USD ($) shares
Subsequent Event [Line Items]
Common stock, shares issued | shares					104,707,116			95,680,831
5.75% Senior convertible notes due August 15, 2018
Subsequent Event [Line Items]
Principal amount					$ 27,690,000			$ 27,690,000
Senior notes, effective interest rate				5.75%
No of convertible shares				29
Principal amount per share | $ / shares				$ 1,000
Percentage of repurchase price				100.00%
Percentage of conversion price equaling stock price				130.00%
Number of trading days | d				20
Senior convertible notes due December 31, 2019
Subsequent Event [Line Items]
Exchange price per share | $ / shares						$ 1.45	$ 1.22
Principal amount					60,000,000			$ 75,000,000
Senior convertible notes due December 31, 2019 | Deerfield
Subsequent Event [Line Items]
Principal amount					$ 45,000,000
Senior notes, effective interest rate					9.75%
Senior convertible notes due December 31, 2019 | Deerfield | Tranche B Exchange Shares
Subsequent Event [Line Items]
Exchange price per share | $ / shares							$ 1.15
Subsequent Event | 5.75% Senior convertible notes due August 15, 2018
Subsequent Event [Line Items]
Principal amount		$ 27,690,000
Subsequent Event | 5.75% Senior convertible notes due October 23, 2021
Subsequent Event [Line Items]
Principal amount		$ 23,690,000
Senior notes, effective interest rate		5.75%
Maturity date		Oct. 23, 2021
No of convertible shares		194.1748
Principal amount per share | $ / shares		$ 1,000
Conversion price of shares | $ / shares		$ 5.15
Percentage of repurchase price		100.00%
Percentage of conversion price equaling stock price		120.00%
Number of trading days | d		10
Consecutive trading days | d		20
Debt instrument, convertible, threshold business days		5 days
Subsequent Event | 5.75% Senior convertible notes due October 23, 2021 | Maximum
Subsequent Event [Line Items]
Common stock, shares issued | shares		13,648,300
Subsequent Event | Senior convertible notes due December 31, 2019 | Fourth Amendment to Facility Agreement
Subsequent Event [Line Items]
Deferred payment of credit facility principal amount		$ 10,000,000
Subsequent Event | Senior convertible notes due December 31, 2019 | Fourth Amendment to Facility Agreement | Deerfield | Tranche B Exchange Shares
Subsequent Event [Line Items]
Conversion price of shares | $ / shares		$ 3.25
Number of trading days | d		3
Subsequent Event | Matthew J. Pfeffer
Subsequent Event [Line Items]
Annual basic salary paid	$ 490,350
Severance payment	$ 345,000
Subsequent Event | Common Stock
Subsequent Event [Line Items]
Number of shares sold in underwritten public offering | shares		973,236
Subsequent Event | Common Stock | Senior convertible notes due December 31, 2019 | Maximum | Fourth Amendment to Facility Agreement | Deerfield | Tranche B Exchange Shares
Subsequent Event [Line Items]
Number of shares sold in underwritten public offering | shares		4,000,000
Subsequent Event | Purchase Agreements
Subsequent Event [Line Items]
Stock purchase agreements date			Oct. 10, 2017
Placement agent fees			5.00%
Subsequent Event | Purchase Agreements | Common Stock
Subsequent Event [Line Items]
Number of shares sold in underwritten public offering | shares			10,166,600
Amount of net proceeds from issuance of securities			$ 57,700,000
Exchange price per share | $ / shares			$ 6.00
Subsequent Event | Charitable Foundation | Common Stock | Director
Subsequent Event [Line Items]
Number of shares sold in underwritten public offering | shares			166,600