Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES:
Net income	$ 21,509	$ 22,998	$ 23,377
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	7,038	6,976	6,712
Compensation for stock options and restricted stock units	4,367	4,018	2,727
Provision for (net recovery of) bad debts	1,001	(23)	2,169
Deferred income tax expense (benefit)	645	(2,016)	(672)
Decrease (increase) in:
Accounts receivable	(4,053)	(4,840)	(8,979)
Inventories, net	(119)	(844)	(27,329)
Prepaid expenses and other current assets	(3,346)	(1,870)	(1,417)
Income tax benefit from exercise of stock options	(969)	(1,135)	(1,593)
Increase (decrease) in:
Accounts payable and accrued liabilities	6,108	(3,079)	4,644
Income taxes payable	(2,028)	3,497	2,998
Customer deposits	353	(1,374)	668
Unearned service revenues	3,772	5,565	5,384
Net cash provided by operating activities	34,278	27,873	8,689
INVESTING ACTIVITIES:
Purchases of property and equipment	(4,350)	(3,843)	(4,474)
Payments for intangible assets	(2,204)	(1,361)	(890)
Net cash used in investing activities	(6,554)	(5,204)	(5,364)
FINANCING ACTIVITIES:
Payments on capital leases	(93)	(132)	(163)
Income tax benefit from exercise of stock options	969	1,135	1,593
Proceeds from issuance of stock, net	5,444	6,162	9,150
Net cash provided by financing activities	6,320	7,165	10,580
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(2,647)	(1,141)	(87)
INCREASE IN CASH AND CASH EQUIVALENTS	31,397	28,693	13,818
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	93,233	64,540	50,722
CASH AND CASH EQUIVALENTS, END OF YEAR	$ 124,630	$ 93,233	$ 64,540