Balance Sheet Account Detail - Summary of Cash and Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Cost of equity securities	$ 5,008	$ 6,310
Foreign currency translation on equity securities	(2,515)	(2,477)
Equity securities, Unrealized Gains	20,592	27,214
Equity Securities, FV-NI, Accumulated Unrealized Loss	0	0
Equity securities (Note 7)	23,085	31,047
Cash, cash equivalents and short-term investments, amortized cost	137,745	198,309
Total cash and cash equivalents and marketable securities, Unrealized Gains	21,296	28,076
Total cash and cash equivalents and marketable securities, Unrealized Losses	(10)	(35)
Cash, cash equivalents, and short-term investments	156,516	223,873
Cash and Cash Equivalents
Schedule of Investments [Line Items]
Equity securities (Note 7)	0	0
Cash, cash equivalents, and short-term investments	85,126	64,418
Marketable Securities
Schedule of Investments [Line Items]
Equity securities (Note 7)	23,085	31,047
Cash, cash equivalents, and short-term investments	71,390	159,455
Money market funds
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	83,987	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	83,987	54,199
Money market funds \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	83,987	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	20,100	62,617
Debt securities, available-for-sale, unrealized gain	193	19
Debt securities, available-for-sale, unrealized loss	0	(10)
Available-for-sale, debt securities, estimated fair value	20,293	62,626
Government-related debt securities \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value		0
Government-related debt securities \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	20,293	62,626
Corporate debt securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	19,693	58,235
Debt securities, available-for-sale, unrealized gain	56	38
Debt securities, available-for-sale, unrealized loss	(10)	(25)
Available-for-sale, debt securities, estimated fair value	19,739	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	19,739	53,248
Bank deposits
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	1,139	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	1,139	5,219
Bank deposits \| Cash and Cash Equivalents
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	1,139	5,219
Bank deposits \| Marketable Securities
Schedule of Investments [Line Items]
Available-for-sale, debt securities, estimated fair value	0	0
Mutual funds
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	3,692	4,375
Debt securities, available-for-sale, unrealized gain	420	783
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	4,112	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	4,112	5,158
Bank CDs
Schedule of Investments [Line Items]
Available-for-sale, debt securities, amortized cost	4,126	7,354
Debt securities, available-for-sale, unrealized gain	35	22
Debt securities, available-for-sale, unrealized loss	0	0
Available-for-sale, debt securities, estimated fair value	4,161	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	$ 4,161	$ 7,376

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