FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Fair Value Assets
Capped call transactions	$ 52,727	$ 0
Cash equivalents
Fair Value Assets
Cash equivalents	450,465	0
Venture Investments
Fair Value Assets
Venture investments	6,640	4,871
Level 1
Fair Value Assets
Capped call transactions	0	0
Level 1 | Cash equivalents
Fair Value Assets
Cash equivalents	450,465	0
Level 1 | Venture Investments
Fair Value Assets
Venture investments	0	0
Level 2
Fair Value Assets
Capped call transactions	52,727	0
Level 2 | Cash equivalents
Fair Value Assets
Cash equivalents	0	0
Level 2 | Venture Investments
Fair Value Assets
Venture investments	0	0
Level 3
Fair Value Assets
Capped call transactions	0	0
Level 3 | Cash equivalents
Fair Value Assets
Cash equivalents	0	0
Level 3 | Venture Investments
Fair Value Assets
Venture investments	$ 6,640	$ 4,871