XML 40 R28.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Marketable Securities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2021
Marketable Securities |
Schedule of marketable debt securities, classified as available-for-sale | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ |  | ​ | ​ |  | Gross |  | Gross |  | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
​ | ​ | Cost | ​ | Gains | ​ | Losses | ​ | Value
​ | ​ | (In thousands)
December 31, 2021 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Marketable securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. government and municipal obligations | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 80,674 | ​ | $ | — | ​ | $ | (133) | ​ | $ | 80,541
Maturing after one year through three years | ​ | ​ | 51,319 | ​ | ​ | — | ​ | ​ | (184) | ​ | ​ | 51,135
Total U.S. government and municipal obligations | ​ | $ | 131,993 | ​ | $ | — | ​ | $ | (317) | ​ | $ | 131,676
Corporate debt securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 170,034 | ​ | $ | — | ​ | $ | (28) | ​ | $ | 170,006
Maturing after one year through three years | ​ | ​ | 67,782 | ​ | ​ | — | ​ | ​ | (357) | ​ | ​ | 67,425
Total corporate debt securities | ​ | $ | 237,816 | ​ | $ | — | ​ | $ | (385) | ​ | $ | 237,431
Total marketable securities | ​ | $ | 369,809 | ​ | $ | — | ​ | $ | (702) | ​ | $ | 369,107
December 31, 2020 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Marketable securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. government and municipal obligations | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 40,328 | ​ | $ | 3 | ​ | $ | (2) | ​ | $ | 40,329
Maturing after one year through three years | ​ | ​ | — | ​ | ​ | — | ​ | ​ | — | ​ | ​ | —
Total U.S. government and municipal obligations | ​ | $ | 40,328 | ​ | $ | 3 | ​ | $ | (2) | ​ | $ | 40,329
Corporate debt securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 110,265 | ​ | $ | 2 | ​ | $ | (10) | ​ | $ | 110,257
Maturing after one year through three years | ​ | ​ | — | ​ | ​ | — | ​ | ​ | — | ​ | ​ | —
Total corporate debt securities | ​ | $ | 110,265 | ​ | $ | 2 | ​ | $ | (10) | ​ | $ | 110,257
Total marketable securities | ​ | $ | 150,593 | ​ | $ | 5 | ​ | $ | (12) | ​ | $ | 150,586
​

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration