CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Operating activities
Net income (loss)	$ (6,402)	$ 4,159
Adjustments to reconcile net income (loss) to net cash and cash equivalents provided by (used in) operating activities:
Depreciation and amortization	3,587	2,877
Net amortization (accretion) of investment premiums and discounts	(67)	53
Equity-based compensation	2,454	3,012
Change in the fair value of acquisition-related contingent consideration	8	(181)
Deferred income taxes		(1)
Loss on disposal of equipment	442
Changes in operating assets and liabilities	2,042	(11,658)
Total adjustments	8,466	(5,898)
Net cash and cash equivalents provided by (used) in operating activities	2,064	(1,739)
Investing activities
Purchases of investments	(24,640)	(21,968)
Proceeds from sales and maturities of investments	24,922	18,916
Purchases of leasehold improvements and equipment	(2,219)	(3,553)
Net cash and cash equivalents used in investing activities	(1,937)	(6,605)
Financing activities
Net proceeds from issuance of common stock	3,199	2,344
Taxes paid related to net share settlement	(819)	(1,988)
Payment of acquisition-related contingent consideration		(174)
Net cash and cash equivalents provided by financing activities	2,380	182
Effect of exchange rate changes on cash	(126)	114
Net increase (decrease) in cash, cash equivalents and restricted cash	2,381	(8,048)
Cash, cash equivalents and restricted cash at beginning of period	20,941	28,645
Cash, cash equivalents and restricted cash at end of period	$ 23,322	$ 20,597