Segment Information - Components of Net Services Revenue (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenue from External Customer [Line Items]
Total net services revenue	$ 23,033	$ 16,924	$ 64,434	$ 47,023
Maintenance and Support [Member]
Revenue from External Customer [Line Items]
Total net services revenue	13,879	11,139	40,064	31,926
Professional Services and Training [Member]
Revenue from External Customer [Line Items]
Total net services revenue	2,774	2,724	8,154	7,495
Subscriptions [Member]
Revenue from External Customer [Line Items]
Total net services revenue	$ 6,380	$ 3,061	$ 16,216	$ 7,602