Revenue - Schedule of Revenues Disaggregated by Revenue Source (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2024	Jul. 01, 2023	Jun. 29, 2024	Jul. 01, 2023
Disaggregation Of Revenue [Line Items]
Revenues, net	$ 202,073	$ 226,830	$ 408,621	$ 468,724
Digital Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	134,551	147,381	272,185	296,725
Workshops + Digital Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	45,682	57,167	93,352	118,855
Clinical Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	19,723	7,592	38,475	7,592
Subscription Revenues, net
Disaggregation Of Revenue [Line Items]
Revenues, net	199,956	212,140	404,012	423,172
Other Revenues, net
Disaggregation Of Revenue [Line Items]
Revenues, net	$ 2,117	$ 14,690	$ 4,609	$ 45,552