CONDENSED UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014
Cash flows from operating activities:
Net loss	$ (13,002)	$ (8,937)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,075	1,129
Stock-based compensation	1,496	1,750
Write-down of inventories	14	96
Gains on disposal of equipment	0	(2)
Write-off of equipment	8	5
Changes in operating assets and liabilities:
Accounts receivable	(81)	1,514
Inventories	2,566	(2,838)
Other assets	421	291
Trade payables	397	(2,106)
Accrued liabilities and deferred revenue	547	(635)
Other long-term liabilities	51	(57)
Net cash used in operating activities	(6,508)	(9,790)
Cash flows from investing activities:
Capital expenditures for property and equipment	(237)	(525)
Proceeds from sale of fixed assets	0	2
Net cash used in investing activities	(237)	(523)
Cash flows from financing activities:
Payment of debt and capital lease obligations	(258)	(268)
Stock issued under share-based compensation, net	394	4,334
Net cash provided by financing activities	136	4,066
Net (decrease) in cash and cash equivalents	(6,609)	(6,247)
Cash and cash equivalents at beginning of period	30,050	37,406
Cash and cash equivalents at end of period	23,441	31,159
Supplemental schedule of non-cash investing and financing activities :
Capital lease obligation to finance capital expenditures	349	448
Purchase of equipment included in accounts payable	$ 125	$ 33