Marketing and Supply Agreement with Eisai - Deferred Revenues under Collaboration with Eisai (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
Less current portion	$ (22,243)	$ (21,425)	[1]
Deferred revenues, less current portion	88,389	87,617	[1]
Eisai
Deferred Revenue Arrangement [Line Items]
Total deferred revenues	92,474	97,687
Less current portion	(14,967)	(18,295)
Deferred revenues, less current portion	77,507	79,392
Eisai | Upfront payments
Deferred Revenue Arrangement [Line Items]
Total deferred revenues	85,048	86,933
Eisai | Net product sales
Deferred Revenue Arrangement [Line Items]
Total deferred revenues	$ 7,426	$ 10,754

[1] The balance sheet data at December 31, 2015, has been derived from audited financial statements at that date. It does not include, however, all of the information and notes required by US generally accepted accounting principles for complete financial statements.