Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	10,000,000	10,000,000
Class A common stock, $0.0001 par value, 600,000,000 shares authorized; 221,081,203 and 207,453,624 shares issued and outstanding as of December 31, 2018 and 2017, respectively [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	600,000,000	600,000,000
Common stock issued (in shares)	221,081,203	207,453,624
Common stock outstanding (in shares)	221,081,203	207,453,624
Class B common stock, $0.0001 par value, 350,000,000 shares authorized; 31,281,638 and 31,302,898 shares issued and outstanding as of December 31, 2018 and 2017, respectively [Member]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock authorized (in shares)	350,000,000	350,000,000
Common stock issued (in shares)	31,281,638	31,302,898
Common stock outstanding (in shares)	31,281,638	31,302,898