CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Revenue:
Revenue	$ 119,023	$ 100,304	$ 220,705	$ 189,654
Cost of revenue:
Cost of revenue	62,618	55,636	118,676	106,643
Gross profit	56,405	44,668	102,029	83,011
Operating expenses:
Research and development	20,921	20,700	41,592	40,030
Sales and marketing	21,343	19,734	41,967	39,073
General and administrative	11,193	9,165	21,862	17,952
Restructuring charges	6,286	0	6,286	0
Total operating expenses	59,743	49,599	111,707	97,055
Loss from operations	(3,338)	(4,931)	(9,678)	(14,044)
Interest and other expense, net:
Interest expense, net	(617)	(142)	(907)	(250)
Other income (expense), net	(109)	123	(94)	(268)
Total interest and other expense, net	(726)	(19)	(1,001)	(518)
Loss before provision for income taxes	(4,064)	(4,950)	(10,679)	(14,562)
Provision for income taxes	148	95	477	250
Net loss	$ (4,212)	$ (5,045)	$ (11,156)	$ (14,812)
Net loss per common share:
Basic and diluted (in dollars per share)	$ (0.07)	$ (0.09)	$ (0.20)	$ (0.27)
Weighted-average number of shares used to compute net income (loss) per common share
Basic (in shares)	57,261	54,624	56,906	54,339
Diluted (in shares)	57,261	54,624	56,906	54,339
Other comprehensive income, net of tax:
Other comprehensive income (loss), net of tax - foreign currency translation adjustments, net	$ 3	$ (223)	$ 249	$ 43
Comprehensive loss	(4,209)	(5,268)	(10,907)	(14,769)
Systems
Revenue:
Revenue	110,841	92,833	205,350	175,193
Cost of revenue:
Cost of revenue	56,721	49,561	107,429	94,162
Services
Revenue:
Revenue	8,182	7,471	15,355	14,461
Cost of revenue:
Cost of revenue	$ 5,897	$ 6,075	$ 11,247	$ 12,481