Balance Sheet Account Detail - Summary of Cash and Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Cost of equity securities	$ 5,008	$ 6,310
Foreign currency translation on equity securities	(2,065)	(2,477)
Equity securities, Unrealized Gains	11,186	27,214
Equity Securities, FV-NI, Accumulated Unrealized Loss	0	0
Equity securities	14,129	31,047
Cash, cash equivalents and short-term investments, amortized cost	188,424	198,309
Total cash and cash equivalents and marketable securities, Unrealized Gains	11,952	28,076
Total cash and cash equivalents and marketable securities, Unrealized Losses	0	(35)
Cash, cash equivalents, and short-term investments	198,311	223,873
Cash and Cash Equivalents
Schedule of Investments [Line Items]
Equity securities	0	0
Cash, cash equivalents, and short-term investments	77,132	64,418
Marketable Securities
Schedule of Investments [Line Items]
Equity securities	14,129	31,047
Cash, cash equivalents, and short-term investments	121,179	159,455
Money market funds
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	59,923	54,199
Debt securities, available-for-sale, unrealized gain	0	0
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	59,923	54,199
Money market funds \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	59,923	54,199
Money market funds \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	0	0
Government-related debt securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	90,232	62,617
Debt securities, available-for-sale, unrealized gain	105	19
Debt securities, available-for-sale, unrealized loss	0	(10)
Available-for-sale, debt securities, estimated fair value	90,337	62,626
Government-related debt securities \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	7,499	0
Government-related debt securities \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	82,838	62,626
Corporate debt securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	16,470	58,235
Debt securities, available-for-sale, unrealized gain	15	38
Debt securities, available-for-sale, unrealized loss		(25)
Available-for-sale, debt securities, estimated fair value	16,485	58,248
Corporate debt securities \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	0	5,000
Corporate debt securities \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	16,485	53,248
Mutual funds
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	3,925	4,375
Debt securities, available-for-sale, unrealized gain	628	783
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	4,553	5,158
Mutual funds \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	0	0
Mutual funds \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	4,553	5,158
Bank CDs
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	3,156	7,354
Debt securities, available-for-sale, unrealized gain	18	22
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	3,174	7,376
Bank CDs \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	0	0
Bank CDs \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	3,174	7,376
Bank deposits
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	9,710	5,219
Debt securities, available-for-sale, unrealized gain	0	0
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	9,710	5,219
Bank deposits \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	9,710	5,219
Bank deposits \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	$ 0	$ 0

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