CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Cash flows from operating activities:
Net loss	$ (24,027)	$ (25,180)
Adjustments to reconcile net loss to net cash used in operating activities:
Amortization of intangibles	2,069	2,783
Depreciation	3,599	3,317
Stock-based compensation	3,251	3,094
Amortization of discount on convertible debt	1,316	1,187
Restructuring, asset impairment and loss on retirement of fixed assets	187	1,675
Amortization of non-cash warrant	416	0
Loss on impairment of long-term investment	0	1,476
Provision for excess and obsolete inventories	387	418
Allowance for doubtful accounts and returns	2,700	739
Other non-cash adjustments, net	72	0
Changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable	14,388	(10,894)
Inventories	942	(51)
Prepaid expenses and other assets	(3,151)	(6,078)
Accounts payable	(6,687)	(3,890)
Deferred revenue	5,435	24,963
Income taxes payable	6	(13)
Accrued and other liabilities	(3,999)	1,046
Net cash used in operating activities	(3,096)	(5,408)
Cash flows from investing activities:
Acquisition of business, net of cash acquired	0	(69,532)
Proceeds from maturities of investments	3,106	7,394
Purchases of property and equipment	3,792	0
Purchases of property and equipment	(3,217)	(2,664)
Net cash provided by (used in) investing activities	3,681	(64,802)
Cash flows from financing activities:
Payment of convertible debt issuance costs	0	(582)
Proceeds from other debts and capital leases	0	262
Repayment of other debts and capital leases	(953)	(114)
Proceeds from common stock issued to employees	2,114	2,074
Payment of tax withholding obligations related to net share settlements of restricted stock units	(2,383)	(955)
Net cash (used in) provided by financing activities	(1,222)	685
Effect of exchange rate changes on cash and cash equivalents	294	330
Net decrease in cash and cash equivalents	(343)	(69,195)
Cash and cash equivalents at beginning of period	55,635	126,190
Cash and cash equivalents at end of period	$ 55,292	$ 56,995