Taxation - Summary of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred tax assets:
Stock compensation expense	$ 4,922	$ 7,936
Alternative minimum tax credit	0	71
Warranty reserve	232	291
Bad debts reserve	131	65
Vacation accrual	188	157
Commissions and other accruals	223	205
Deferred rent liability	36	53
Equipment	92	69
Intangible assets	921	778
Net operating loss carryforwards	1,833	1,868
Total deferred tax assets	8,578	11,493
Deferred tax liabilities:
Equipment	(1,610)	(1,466)
Prepaid expenses	(285)	(200)
Patents	(628)	(489)
Goodwill	(3,792)	(3,193)
Other	(12)	(16)
Total deferred tax liabilities	(6,327)	(5,364)
Net deferred tax asset before valuation allowance	2,251	6,129
Valuation allowances for deferred tax assets	(1,833)	(1,868)	(1,327)	(1,102)
Net deferred tax asset	$ 418	$ 4,261