Stockholders' Equity (Deficit) (Details)	12 Months Ended
	Dec. 31, 2019 vote $ / shares shares	Dec. 31, 2018 $ / shares shares
Stockholders' Equity
Preferred stock, shares authorized (in shares)	10,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.001
Preferred stock, shares issued (in shares)	0
Preferred stock, shares outstanding (in shares)	0
Class A common stock
Common stock
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001
Common stock, shares outstanding (in shares)	66,642,611	62,329,701
Number of votes each holder is entitled | vote	1
Class B common stock
Common stock
Common stock, shares authorized (in shares)	164,000,000	164,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.001	$ 0.001
Common stock, shares outstanding (in shares)	26,957,815	28,417,882
Number of votes each holder is entitled | vote	10
Conversion ratio	1
Conversion ratio upon transfer	1
Number of shares converted into Class A shares (in shares)	55,081,618
Class B common stock | Minimum
Common stock
Percentage of outstanding shares of class B common stock that shall convert automatically in event of affirmative vote or written consent of holders for automatic conversion	66.67%
Class B common stock | Maximum
Common stock
Aggregate number of shares outstanding Class A common stock and Class B common stock that will automatically convert (less than)	10.00%