Stock Based Compensation - Stock Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	$ 624	$ 628	$ 1,710	$ 1,254
Cost of Sales [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	81	49	162	98
Service, Rental and Maintenance [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	(17)	20	22	40
Selling and Marketing [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	131	119	262	238
General and Administrative [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	$ 429	$ 440	$ 1,264	$ 878