Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)
Significant Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 0	$ 0
Amortization period description	The amortization period begins with the first month of availability on our service.
Number of reporting unit | Segment	1
Impairment of goodwill	$ 0	0
Impairment of long-lived assets	0	0
Marketing and advertising costs	$ 30,500,000	31,300,000
Defined contribution plan percentage employee's matching contribution	50.00%
Defined contribution plan maximum annual matching contribution amount	$ 3,000
Impairment charges on cost method investments	0	0
Defined Contribution Plan 401 (k) [Member]
Significant Accounting Policies [Line Items]
Defined contribution plan annual matching contribution amount	300,000	$ 300,000
A La Carte Course Purchase [Member]
Significant Accounting Policies [Line Items]
Assets	0
Liabilities	$ 0
Website Development Costs and Other Software [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
License period or estimated useful life of media library	12 months
Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	45 years
License period or estimated useful life of media library	90 months
Investments in Unconsolidated Subsidiaries, Joint Ventures, and Other Investees [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Percentage of interest in investments	20.00%
Investments in Unconsolidated Subsidiaries, Joint Ventures, and Other Investees [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Percentage of interest in investments	50.00%