Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 02, 2016		Apr. 04, 2015
Cash flows from operating activities:
Net loss	$ (1,154)		$ (1,687)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	1,455		1,626
Amortization of intangibles and other	643		641
Amortization of security discount (premium)	69		(87)
Stock-based compensation	3,479		4,391
Changes in operating assets and liabilities:
Accounts receivable	(22,635)		2,152
Inventories	4,421		(3,068)
Prepaid expenses and other current assets	670		149
Other assets	(59)		(227)
Accounts payable	941		1,507
Deferred product and services income	1,651		(406)
Other current liabilities	2,029		492
Other liabilities	(404)		(580)
Net cash (used in) provided by operating activities	(8,894)		4,903
Cash flows from investing activities:
Capital expenditures	(185)		(1,126)
Purchase of investments in securities	(21,100)		(40,088)
Proceeds from maturities of investments	42,943		45,098
Net cash provided by investing activities	21,658		3,884
Cash flows from financing activities:
Proceeds from notes payable	5,120		5,120
Repayment of notes payable	(5,120)		(5,120)
Proceeds from issuance of common stock for stock option exercises	305		87
Tax payment for issuance of common stock from release of restricted stock units	(1,737)		(1,735)
Net cash used in financing activities	(1,432)		(1,648)
Net increase in cash and cash equivalents	11,332		7,139
Cash and cash equivalents at beginning of period	63,008	[1]	67,988
Cash and cash equivalents at end of period	74,340		75,127
Other non-cash changes:
Systems transferred from (to) inventory to (from) equipment and other assets, net	$ 0		$ (1,524)

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