Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2020	Mar. 30, 2019
Cash Flows from Operating Activities
Net income (loss)	$ 20,294	$ (79,465)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Provision for doubtful accounts	6,486	32
Provision for excess and obsolete inventory	9,845	1,478
Depreciation	10,589	13,373
Non-cash lease expense	1,524	7,713
Accelerated depreciation of property and equipment	13	0
Amortization of intangible assets	4,029	2,060
Stock-based compensation	19,727	20,544
Deferred income taxes	46	(20)
Other	5	(50)
Changes in operating assets and liabilities, net of acquisition:
Accounts receivable	246,499	163,592
Inventories	20,301	(50,958)
Prepaid expenses and other assets	(28,073)	12,554
Increase (Decrease) in Income Taxes Receivable	(139,254)	40
Fitbit Force recall reserve	(41)	46
Accounts payable	(104,378)	(81,656)
Accrued liabilities and other liabilities	(143,692)	(69,962)
Lease liabilities	(4,756)	(4,972)
Deferred revenue	(2,200)	(2,259)
Income taxes payable	1,064	257
Net cash used in operating activities	(81,972)	(67,653)
Cash Flows from Investing Activities
Purchase of property and equipment	(3,556)	(6,096)
Purchases of marketable securities	(59,735)	(111,615)
Maturities of marketable securities	68,191	128,309
Net cash provided by investing activities	4,900	10,598
Cash Flows from Financing Activities
Payment of financing lease liability	0	(597)
Proceeds from issuance of common stock	458	931
Taxes paid related to net share settlement of restricted stock units	(5,868)	(6,422)
Net cash used in financing activities	(5,410)	(6,088)
Net decrease in cash and cash equivalents	(82,482)	(63,143)
Cash and cash equivalents at beginning of period	334,479	473,956
Cash and cash equivalents at end of period	$ 251,997	$ 410,813