Quarterly report pursuant to Section 13 or 15(d)

Cover
- Cover Page
Financial Statements
Notes to Financial Statements
Accounting Policies
- Basis of Presentation and Summary of Significant Accounting Policies (Policies)
Notes Tables
Notes Details

Basis of Presentation and Summary of Significant Accounting Policies - Investment Categories (Details)

v3.20.2

Basis of Presentation and Summary of Significant Accounting Policies - Investment Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Equity Securities, FV-NI [Abstract]
Estimated fair value	$ 8,816	$ 9,910
Debt and Equity Securities, FV-NI [Abstract]
Amortized cost	643,813	941,174
Gross unrealized gains	1,291	933
Gross unrealized losses	(2,731)	(2,118)
Estimated fair value	642,373	939,989
Bank deposits
Debt Securities, Available-for-sale [Line Items]
Amortized cost	269,114	411,690
Gross unrealized gains	221	188
Gross unrealized losses	(56)	(3)
Estimated fair value	269,279	411,875
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized cost	55,380	63,818
Gross unrealized gains	125	161
Gross unrealized losses	(94)	0
Estimated fair value	55,411	63,979
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized cost	163,590	210,525
Gross unrealized gains	134	43
Gross unrealized losses	0	(16)
Estimated fair value	163,724	210,552
Corporate equity securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	4,506	4,506
Gross unrealized gains	634	416
Gross unrealized losses	(2,484)	(1,850)
Estimated fair value	2,656	3,072
Mutual fund
Debt Securities, Available-for-sale [Line Items]
Amortized cost	151,223	250,635
Gross unrealized gains	0	0
Gross unrealized losses	(97)	(249)
Estimated fair value	151,126	250,386
Warrants
Equity Securities, FV-NI [Abstract]
Amortized cost	0	0
Gross unrealized gains	177	125
Gross unrealized losses	0	0
Estimated fair value	$ 177	$ 125

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