Basis of Presentation and Summary of Significant Accounting Policies - Disaggregation of Revenue by Payor Type (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 176,783	$ 180,123	$ 165,169	$ 165,105	$ 178,751	$ 156,060	$ 130,050	$ 95,757	$ 687,180	$ 560,618	$ 519,908
Commercial
Disaggregation of Revenue [Line Items]
Revenue									108,851	107,340	113,000
Medicare
Disaggregation of Revenue [Line Items]
Revenue									271,596	226,002	226,353
Medicaid
Disaggregation of Revenue [Line Items]
Revenue									269,079	192,596	134,904
Other third parties
Disaggregation of Revenue [Line Items]
Revenue									$ 37,654	$ 34,680	$ 45,651