Schedule of Accounts Payable and Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Accounts Payable and Accrued Liabilities [Line Items]
Accounts payable	$ 1,654	$ 2,020
Payable to benefit providers and transit agencies	16,802	17,519
Accrued payables	6,198	6,239
Accrued compensation and related benefits	8,160	12,153
Other accrued expenses	1,505	1,994
Deferred revenue	3,168	2,109
Accounts payable and accrued expenses	$ 37,487	$ 42,034