Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2016		Oct. 03, 2015
Cash flows from operating activities:
Net income (loss)	$ 6,913		$ (6,247)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	4,179		4,830
Amortization of intangibles and other	2,024		1,595
Amortization of security premium	(125)		(110)
Stock-based compensation	9,329		11,858
Changes in operating assets and liabilities:
Accounts receivable	(18,484)		13,388
Inventories	13,147		(9,987)
Prepaid expenses and other current assets	(1,236)		1,333
Other assets	(742)		(191)
Accounts payable	1,181		2,280
Deferred product and services income	676		(3,536)
Other current liabilities	4,878		924
Other liabilities	(1,287)		(1,601)
Net cash provided by operating activities	20,453		14,536
Cash flows from investing activities:
Capital expenditures	(1,663)		(2,095)
Purchase of investments in securities	(137,174)		(153,551)
Proceeds from maturities of investments	161,154		185,052
Net cash provided by investing activities	22,317		29,406
Cash flows from financing activities:
Proceeds from notes payable	7,320		15,360
Repayment of notes payable	(11,340)		(15,360)
Proceeds from issuance of common stock for stock option exercises	1,841		262
Tax payment for issuance of common stock from release of restricted stock units	(1,923)		(1,856)
Payments for Repurchase of Common Stock	0		21,438
Net cash used in financing activities	(4,102)		(23,032)
Net increase in cash and cash equivalents	38,668		20,910
Cash and cash equivalents at beginning of period	63,008	[1]	67,988
Cash and cash equivalents at end of period	101,676		88,898
Other non-cash changes:
Systems transferred from (to) inventory to (from) equipment and other assets, net	$ 0		$ 817

[1] The balance sheet as of December 31, 2015 has been derived from the audited financial statements at that date.