Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash Flows from Operating Activities:
Net income	$ 7,275	$ 7,755
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,267	2,948
Loss (gain) on write down / disposal of property and equipment, net	17	(29)
Loss on disposal of intangibles	126	111
Bond premium amortization	428	69
Provision for doubtful accounts	84	1
Provision for excess and obsolete inventory	15	169
Provision for warranty	426	506
Stock-based compensation expense	2,684	1,943
Deferred income taxes	7,910	3,799
Provision for unrecognized tax benefits	(1,257)	170
Excess tax benefit from stock-based compensation	(5,516)	(3,880)
Change in assets and liabilities:
Accounts and notes receivable	(663)	1,211
Inventory	(4,017)	(2,376)
Prepaid expenses and other assets	(3,689)	(3,777)
Accounts payable and accrued liabilities	(3,282)	(600)
Deferred revenue	3,920	3,468
Customer deposits	(766)	735
Net cash provided by operating activities	5,962	12,223
Cash Flows from Investing Activities:
Purchases of investments	(17,312)	(12,677)
Proceeds from call / maturity of investments	4,200	1,680
Purchases of property and equipment	(1,222)	(839)
Proceeds from disposal of fixed assets	0	34
Purchases of intangible assets	(109)	(202)
Net cash used in investing activities	(14,443)	(12,004)
Cash Flows from Financing Activities:
Repurchase of common stock	(19,552)	(25,000)
Proceeds from options exercised	7,372	4,051
Payroll tax payments for net-settled stock awards	(1,190)	(185)
Excess tax benefit from stock-based compensation	5,516	3,880
Payments on capital lease obligation	(18)	(17)
Net cash used in financing activities	(7,872)	(17,271)
Effect of exchange rate change on cash and cash equivalents	25	5
Net decrease in cash and cash equivalents	(16,328)	(17,047)
Cash and cash equivalents, beginning of period	42,271	36,127
Cash and cash equivalents, end of period	25,943	19,080
Supplemental Disclosure:
Cash paid for income taxes-net	367	2,292
Non-Cash Transactions:
Property and equipment purchases in accounts payable	$ 75	$ 51