Fair Value of Financial Instruments (Details) - Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2020
Assets [Abstract]
Cash equivalents	$ 79,564	$ 179,900
Investments	216,041	156,046
Fair value of financial instruments	295,605	335,946
Money Market Mutual Funds [Member]
Assets [Abstract]
Cash equivalents	79,564	179,900
United States Treasury Securities [Member]
Assets [Abstract]
Investments	134,748	44,045
Corporate Bonds [Member]
Assets [Abstract]
Investments	81,293	96,696
Municipal Bonds [Member]
Assets [Abstract]
Investments		6,000
Agency Bonds [Member]
Assets [Abstract]
Investments		9,305
Level 1 [Member]
Assets [Abstract]
Cash equivalents	79,564	179,900
Investments	134,748	44,045
Fair value of financial instruments	214,312	223,945
Level 1 [Member] \| Money Market Mutual Funds [Member]
Assets [Abstract]
Cash equivalents	79,564	179,900
Level 1 [Member] \| United States Treasury Securities [Member]
Assets [Abstract]
Investments	134,748	44,045
Level 1 [Member] \| Corporate Bonds [Member]
Assets [Abstract]
Investments	0	0
Level 1 [Member] \| Municipal Bonds [Member]
Assets [Abstract]
Investments		0
Level 1 [Member] \| Agency Bonds [Member]
Assets [Abstract]
Investments		0
Level 2 [Member]
Assets [Abstract]
Cash equivalents	0	0
Investments	81,293	112,001
Fair value of financial instruments	81,293	112,001
Level 2 [Member] \| Money Market Mutual Funds [Member]
Assets [Abstract]
Cash equivalents	0	0
Level 2 [Member] \| United States Treasury Securities [Member]
Assets [Abstract]
Investments	0	0
Level 2 [Member] \| Corporate Bonds [Member]
Assets [Abstract]
Investments	81,293	96,696
Level 2 [Member] \| Municipal Bonds [Member]
Assets [Abstract]
Investments		6,000
Level 2 [Member] \| Agency Bonds [Member]
Assets [Abstract]
Investments		9,305
Level 3 [Member]
Assets [Abstract]
Cash equivalents	0	0
Investments	0	0
Fair value of financial instruments	0	0
Level 3 [Member] \| Money Market Mutual Funds [Member]
Assets [Abstract]
Cash equivalents	0	0
Level 3 [Member] \| United States Treasury Securities [Member]
Assets [Abstract]
Investments	0	0
Level 3 [Member] \| Corporate Bonds [Member]
Assets [Abstract]
Investments	$ 0	0
Level 3 [Member] \| Municipal Bonds [Member]
Assets [Abstract]
Investments		0
Level 3 [Member] \| Agency Bonds [Member]
Assets [Abstract]
Investments		$ 0

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

No definition available.

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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