CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2021	Sep. 25, 2020
Cash flows from operating activities:
Net income (loss)	$ (6,603)	$ (42,736)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	9,395	8,683
Amortization of intangibles	507	3,214
Stock-based compensation	18,863	13,737
Amortization of convertible debt discount	4,685	5,451
Amortization of warrant	1,302	1,307
Foreign currency remeasurement	(3,435)	2,537
Loss on convertible debt extinguishment	0	834
Deferred income taxes	1,268	1,527
Provision for expected credit losses and returns	3,049	1,966
Provision for excess and obsolete inventories	1,849	1,390
Other adjustments	215	177
Changes in operating assets and liabilities:
Accounts receivable	(12,470)	5,436
Inventories	(18,783)	(9,301)
Other assets	2,614	23,685
Accounts payable	10,144	(11,047)
Deferred revenues	9,978	6,066
Other liabilities	11,078	(15,345)
Net cash provided by (used in) operating activities	33,656	(2,419)
Cash flows from investing activities:
Purchases of property and equipment	(10,570)	(26,176)
Net cash used in investing activities	(10,570)	(26,176)
Cash flows from financing activities:
Payment of convertible debt	0	(25)
Payment of convertible debt issuance costs	0	(672)
Proceeds from other debts	3,861	9,398
Repayment of other debts	(6,070)	(6,342)
Proceeds from common stock issued to employees	11,401	5,227
Payment of tax withholding obligations related to net share settlements of restricted stock units	(1,619)	(1,384)
Net cash provided by financing activities	7,573	6,202
Effect of exchange rate changes on cash and cash equivalents	(870)	152
Net increase (decrease) in cash and cash equivalents	29,789	(22,241)
Cash and cash equivalents at beginning of period	98,645	93,058
Cash and cash equivalents at end of period	128,434	70,817
Supplemental disclosures of cash flow information:
Income taxes, net of refunds	1,732	(426)
Interest payments	3,242	3,216
Supplemental schedule of non-cash investing and financing activities:
Capital expenditures incurred but not yet paid	1,055	3,284
Fair value of 2022 Notes used to settle 2020 Notes	$ 0	$ 44,357