Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash Flows from Operating Activities:
Net income	$ 3,391	$ 3,298
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,162	1,419
Loss (gain) on write down / disposal of property and equipment, net	15	(29)
Loss on disposal of intangibles	80	96
Bond premium amortization	192
Provision for doubtful accounts	1
Provision for excess and obsolete inventory	7	46
Provision for warranty	306	169
Stock-based compensation expense	1,177	923
Deferred income taxes	6,401	1,732
Provision for unrecognized tax benefits	(1,285)	58
Excess tax benefit from stock-based compensation	(4,723)	(1,910)
Change in assets and liabilities:
Accounts and notes receivable	1,986	1,294
Inventory	(2,150)	(894)
Prepaid Expenses and other assets	(4,574)	(1,134)
Accounts payable and accrued liabilities	1,628	(2,093)
Deferred revenue	1,307	1,659
Customer deposits	(611)	(115)
Net cash provided by operating activities	4,310	4,519
Cash Flows from Investing Activities:
Purchases of investments	(13,822)
Proceeds from call / maturity of investments	2,380	1,680
Purchases of property and equipment	(799)	(383)
Proceeds from disposal of fixed assets		34
Purchases of intangible assets	(67)	(104)
Net cash provided by (used in) investing activities	(12,308)	1,227
Cash Flows from Financing Activities:
Repurchase of common stock		(5,351)
Proceeds from options exercised	7,275	307
Payroll tax payments for net-settled stock awards	(1,138)	(178)
Excess tax benefit from stock-based compensation	4,723	1,910
Payments on capital lease obligation	(8)	(8)
Net cash provided by (used in) financing activities	10,852	(3,320)
Effect of exchange rate change on cash and cash equivalents	8	27
Net increase in cash and cash equivalents	2,862	2,453
Cash and cash equivalents, beginning of period	42,271	36,127
Cash and cash equivalents, end of period	45,133	38,580
Supplemental Disclosure:
Cash paid for income taxes-net	50	50
Non-Cash Transactions:
Property and equipment purchases in accounts payable	$ 114	$ 227