Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 13,308	$ 7,275
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,362	2,267
Loss on write-down / disposal of property and equipment, net	0	17
Loss on disposal of intangibles	165	126
Bond premium amortization	826	428
Change in provision for doubtful accounts	(44)	84
Change in provision for excess and obsolete inventory	(85)	15
Change in provision for warranty expense	(19)	426
Stock-based compensation	3,223	2,684
Deferred income taxes	(511)	7,910
Unrecognized tax benefits	(319)	(1,257)
Excess tax benefit from stock-based compensation	(6,245)	(5,516)
Change in assets and liabilities:
Accounts and notes receivable	5,613	(663)
Inventory	(5,244)	(4,017)
Prepaid expenses and other assets	(8,174)	(3,689)
Accounts payable, accrued and other liabilities	3,646	(3,282)
Deferred revenue	3,133	3,920
Customer deposits	334	(766)
Net cash provided by operating activities	10,969	5,962
Cash flows from investing activities:
Purchases of investments	(38,750)	(17,312)
Proceeds from call / maturity of investments	21,365	4,200
Purchases of property and equipment	(1,770)	(1,222)
Purchases of intangible assets	(201)	(109)
Business acquisition, net of cash acquired	7,840
Net cash used in investing activities	(27,196)	(14,443)
Cash flows from financing activities:
Repurchase of common stock	0	(19,552)
Proceeds from options exercised	2,553	7,372
Payroll tax payments for net-settled stock awards	(647)	(1,190)
Payments on capital lease obligation	(18)	(18)
Excess tax benefit from stock-based compensation	6,245	5,516
Net cash provided by (used in) financing activities	8,133	(7,872)
Effect of exchange rate changes on cash and cash equivalents	81	25
Net decrease in cash and cash equivalents	(8,013)	(16,328)
Cash and cash equivalents, beginning of period	48,367	42,271
Cash and cash equivalents, end of period	40,354	25,943
Supplemental disclosure:
Cash paid for income taxes, net	4,848	367
Non-cash transactions
Property and equipment purchases in accounts payable and accrued liabilities	$ 205	$ 75