Investments and Fair Value Measurement - Narrative (Details) - USD ($) $ in Thousands |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2020 |
Mar. 31, 2019 |
Dec. 31, 2019 |
|
| Marketable Securities [Line Items] | |||
| Allowance for credit loss | $ 173,000 | $ 0 | |
| Change in unrealized loss on investments in available-for-sale securities | (60,000) | $ (4,000) | |
| Grab | |||
| Marketable Securities [Line Items] | |||
| Allowance for credit loss | $ 173,000 | ||
| Market adjustment | 10.00% | ||
| Reduction In carrying value | $ 230,000 | ||
| Change in unrealized loss on investments in available-for-sale securities | (57,000) | ||
| Didi | |||
| Marketable Securities [Line Items] | |||
| Impairment loss | 1,700,000 | ||
| Pro Forma | |||
| Marketable Securities [Line Items] | |||
| Interest income | $ 36,000 | $ 34,000 | |
| Common Stock Equivalent | |||
| Marketable Securities [Line Items] | |||
| Valuation technique, weight | 80.00% | ||
| Option Pricing Model | |||
| Marketable Securities [Line Items] | |||
| Valuation technique, weight | 20.00% | ||