Acquisition (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Preliminary purchase price allocation
Purchase price	$ 45,974
Less: acquired cash	(8,856)
Purchase price, net of acquired cash	37,118
Accounts receivable	3,327
Intangible assets	13,255
Other assets	1,729
Deferred tax liability, net	(2,284)
Accounts payable, accrued expenses and deferred revenue	(5,084)
Goodwill	$ 26,175