Components of Prepaid Expenses and Other (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	$ 8,143	$ 7,660
Prepaid expenses and other, long-term	9,284	9,597
Totals	17,427	17,257
CRO services
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	3,133	2,969
Prepaid expenses and other, long-term	6,045	5,754
Other clinical development
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	2,204	2,309
Prepaid expenses and other, long-term	2,466	3,005
Insurance
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	852	1,138
Prepaid expenses and other, long-term	90	87
Other
Prepaid Expenses [Line Items]
Prepaid expenses and other, current	1,954	1,244
Prepaid expenses and other, long-term	$ 683	$ 751