Redeemable Convertible Preferred Units - Redeemable Convertible Preferred Units (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
Series A1 Preferred Stock
Issued Units | shares	109,838
Liquidation Preference	$ 133,546
Initial Carrying Amount	$ 109,838
Series A1 Preferred Stock | 2017
Year of Issuance	2017
Authorized Units | shares	110,898
Issued Units | shares	87,000
Issuance Price per Unit | $ / shares	$ 1.00
Liquidation Preference	$ 106,978
Initial Carrying Amount	$ 87,000
Series A1 Preferred Stock | 2018
Year of Issuance	2018
Authorized Units | shares	110,898
Issued Units | shares	22,838
Issuance Price per Unit | $ / shares	$ 1.00
Liquidation Preference	$ 26,568
Initial Carrying Amount	$ 22,838
Series A Preferred Stock
Issued Units | shares	16,126
Liquidation Preference	$ 23,316
Initial Carrying Amount	$ 19,761
Series A Preferred Stock | 2017
Year of Issuance	2017
Authorized Units | shares	23,600
Issued Units | shares	11,741
Issuance Price per Unit | $ / shares	$ 1.00
Liquidation Preference	$ 14,504
Initial Carrying Amount	$ 11,741
Series A Preferred Stock | 2018
Year of Issuance	2018
Authorized Units | shares	23,600
Issued Units | shares	1,500
Issuance Price per Unit | $ / shares	$ 1.50
Liquidation Preference	$ 2,536
Initial Carrying Amount	$ 2,250
Series A Preferred Stock | 2019
Year of Issuance	2019
Authorized Units | shares	23,600
Issued Units | shares	2,885
Issuance Price per Unit | $ / shares	$ 2.00
Liquidation Preference	$ 6,276
Initial Carrying Amount	$ 5,770