Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities
Net income	$ 30,760	$ 30,518	$ 23,979
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	25,639	20,272	18,365
Loss on disposal of fixed assets	238	167	345
Impairment of equity investments	0	350	1,759
Gain on equity investments	(3,443)	0
Provision for receivable allowance	354	941	110
Share-based compensation expense	14,921	12,785	11,151
Income tax benefits from employee stock plans	4,535	5,370	2,576
Excess tax benefits from employee stock plans	(4,724)	(5,834)	(3,673)
Provision for excess and obsolete inventories	369	542	856
Deferred income taxes	(1,092)	1,402	787
Changes in operating assets and liabilities, net of business acquisitions:
Accounts receivable, net	(18,295)	(22,799)	(3,609)
Inventories	(10,401)	1,418	(5,410)
Prepaid expenses	4,049	(4,296)	(3,491)
Other current assets	638	53	1,566
Net investment in sales-type leases	(4,661)	1,048	1,723
Other long-term assets	496	297	630
Accounts payable	(2,841)	1,611	(1,784)
Accrued compensation	(2,032)	270	7,991
Accrued liabilities	5,456	5,512	1,758
Deferred service revenue	(2,880)	5,086	82
Deferred gross profit	(2,641)	8,601	(815)
Other long-term liabilities	(683)	1,849	367
Net cash provided by operating activities	33,762	65,163	55,263
Investing Activities
Acquisition of intangible assets, intellectual property and patents	(415)	(327)	(356)
Software development for external use	(12,132)	(10,353)	(7,761)
Purchases of property and equipment	(7,542)	(11,922)	(12,335)
Business acquisitions, net of cash acquired	(25,507)	(20,723)	0
Net cash used in investing activities	(45,596)	(43,325)	(20,452)
Financing Activities
Proceeds from issuances under stock-based compensation plans	17,091	21,795	26,886
Employees' taxes paid related to restricted stock units	(3,627)	(3,744)	(2,223)
Common stock repurchases	(50,021)	(24,091)	(20,962)
Excess tax benefits from employee stock plans	4,724	5,834	3,673
Net cash provided by (used in) financing activities	(31,833)	(206)	7,374
Effect of exchange rate changes on cash and cash equivalents	(4)	(275)	33
Net increase (decrease) in cash and cash equivalents	(43,671)	21,357	42,218
Cash and cash equivalents at beginning of period	125,888	104,531	62,313
Cash and cash equivalents at end of period	82,217	125,888	104,531
Supplemental cash flow information
Cash paid for interest	76	61	122
Cash paid for taxes, net of refunds	11,871	9,161	7,062
Supplemental disclosure of non-cash investing activities
Non-cash activity business acquisition	7,386	0	0
Unpaid property and equipment purchases	$ 1,398	$ 273	$ 1,696