Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts receivable allowance	$ 22,774	$ 9,312
Convertible redeemable preferred units, par value (in dollars per share)	$ 0.001	$ 0.001
Convertible redeemable preferred units, shares authorized (in shares)	10,000,000	10,000,000
Convertible redeemable preferred units, shares issued (in shares)	0	0
Class A common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	66,642,611	62,329,701
Common stock, shares outstanding (in shares)	66,642,611	62,329,701
Class B common stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	164,000,000	164,000,000
Common stock, shares issued (in shares)	26,957,815	28,417,882
Common stock, shares outstanding (in shares)	26,957,815	28,417,882

Amount of allowance for credit loss on accounts receivable, classified as current.

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