Stock Based Compensation - Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	$ 394	$ 1,106	$ 1,497	$ 2,816
Cost of Revenue [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	33	108	101	270
Service, Rental and Maintenance [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	29	56	86	78
Selling and Marketing [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	16	151	118	413
General and Administrative [Member]
Share based Compensation Allocation of Recognized Period Cost [Line Items]
Total stock based compensation	$ 316	$ 791	$ 1,192	$ 2,055