Stockholders' Equity - Summary of Stock-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total stock-based compensation expense	$ 8,009	$ 7,654	$ 7,075
Instructional costs and services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total stock-based compensation expense	1,254	1,480	1,535
Selling and promotional
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total stock-based compensation expense	823	771	1,007
General and administrative
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total stock-based compensation expense	$ 5,932	$ 5,403	$ 4,533