Going Concern - Additional Information (Detail) - USD ($) $ in Thousands			6 Months Ended
	Apr. 05, 2017	Apr. 03, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Dec. 22, 2015	Jul. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Unrestricted cash and cash equivalents			$ 135,501	$ 17,200	$ 21,524	$ 21,491	$ 185,606
Special cash dividend distributed	$ 140,000
Dividend paid date			May 26, 2017
Dividend payable, date of record			May 17, 2017
Aggregate principal amount outstanding redeemed			$ 175,000
Convertible Notes [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Interest rate (as a percent)		4.50%							4.50%
Deposited into escrow account		$ 60,000	$ 60,000
2022 Notes [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Interest rate (as a percent)								11.50%
Asset Sale Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Special cash dividend distributed		$ 140,000
Asset Sale Agreement [Member] | 2022 Notes [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Interest rate (as a percent)		11.50%
Aggregate principal amount outstanding redeemed		$ 175,000
Additional premium payment		20,100
Ipsen [Member] | Asset Sale Agreement [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront cash payment received		575,000
Working capital adjustment receivable		$ 2,200