Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Allowance for accounts receivable	$ 472	$ 340
STOCKHOLDERS'/MEMBERS' EQUITY:
Preferred stock, par value (in dollars per share)	$ 0.001
Preferred stock, shares authorized	10,000,000
Preferred stock, shares issued	0
Preferred stock, shares outstanding	0
Class A
STOCKHOLDERS'/MEMBERS' EQUITY:
Common stock, par value (in dollars per share)	$ 0.001
Common stock, shares authorized	750,000,000
Common stock, shares issued	35,937,500
Common stock, shares outstanding	35,937,500
Class B
STOCKHOLDERS'/MEMBERS' EQUITY:
Common stock, par value (in dollars per share)	$ 0.001
Common stock, shares authorized	300,000,000
Common stock, shares issued	173,624,316
Common stock, shares outstanding	173,624,316
Class C
STOCKHOLDERS'/MEMBERS' EQUITY:
Common stock, par value (in dollars per share)	$ 0.001
Common stock, shares authorized	75,000,000
Common stock, shares issued	42,944,647
Common stock, shares outstanding	42,944,647