Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounts receivable, allowance	$ 0	$ 0
Common stock, par value	$ 0.00000625	$ 0.00000625
Common stock, shares authorized	2,020,517,000	2,020,517,000
Common stock, shares outstanding	860,181,000	870,660,000
Common Class A [Member]
Common stock, shares outstanding	860,181,000	783,376,000
Common Class B [Member]
Common stock, shares outstanding		66,767,000
Common Class C [Member]
Common stock, shares outstanding		20,517,000