Revenue - Schedule of Revenues Disaggregated by Revenue Source (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2025	Mar. 30, 2024
Disaggregation Of Revenue [Line Items]
Revenues, net	$ 186,571	$ 206,548
Digital Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	120,431	137,633
Workshops + Digital Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	35,292	47,671
Behavioral Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	155,723	185,304
Clinical Subscription Revenues
Disaggregation Of Revenue [Line Items]
Revenues, net	29,457	18,752
Subscription Revenues, net
Disaggregation Of Revenue [Line Items]
Revenues, net	185,180	204,056
Other Revenues, net
Disaggregation Of Revenue [Line Items]
Revenues, net	$ 1,391	$ 2,492