CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 27, 2019	Sep. 28, 2018
Cash flows from operating activities:
Net income (loss)	$ (11,494)	$ (24,365)
Adjustments to reconcile net loss to net cash provided by operating activities:
Amortization of intangibles	6,242	6,281
Depreciation	8,480	9,910
Stock-based compensation	8,719	14,202
Amortization of discount on convertible debt and issuance cost	4,960	4,482
Amortization of non-cash warrant	13,137	1,185
Restructuring, asset impairment and loss on retirement of fixed assets	85	1,105
Loss on debt extinguishment	5,695	0
Deferred income taxes, net	75	1,056
Foreign currency adjustments	(1,719)	(1,034)
Provision for excess and obsolete inventories	704	1,259
Allowance for doubtful accounts and returns	988	1,357
Other non-cash adjustments, net	1,150	286
Changes in operating assets and liabilities:
Accounts receivable	(20,521)	(9,585)
Inventories	(4,170)	997
Prepaid expenses and other assets	(5,703)	2,507
Accounts payable	(2,839)	(4,032)
Deferred revenue	8,002	1,783
Income taxes payable	(114)	461
Accrued and other liabilities	(10,536)	(2,188)
Net cash provided by operating activities	1,141	5,667
Cash flows from investing activities:
Proceeds from sales of investments	0	104
Purchases of property and equipment	(4,973)	(4,703)
Net cash used in investing activities	(4,973)	(4,599)
Cash flows from financing activities:
Proceeds from convertible debt	115,500
Payments of convertible debt	(109,603)
Payment of convertible debt issuance costs	(3,465)	0
Proceeds from other debts and finance leases	4,684	5,066
Repayment of other debts and finance leases	(6,387)	(6,568)
Proceeds from common stock issued to employees	5,573	4,299
Payment of tax withholding obligations related to net share settlements of restricted stock units	(1,278)	(166)
Net cash provided by financing activities	5,024	2,631
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(486)	(580)
Net increase in cash, cash equivalents and restricted cash	706	3,119
Cash, cash equivalents and restricted cash at beginning of period	65,989	58,757
Cash, cash equivalents and restricted cash at end of period	66,695	61,876
Supplemental disclosures of cash flow information:
Income tax payments, net	980	1,209
Interest payments, net	3,432	2,727
Supplemental schedule of non-cash investing and financing activities:
Capital expenditures incurred but not yet paid	543	664
Issuance of warrant	16,142	2,295
Reconciliation of cash, cash equivalents, and restricted cash to the condensed consolidated balance sheets
Total cash, cash equivalents and restricted cash	$ 65,989	$ 58,757