XML 19 R9.htm IDEA: XBRL DOCUMENT
v3.21.2

Marketable Securities | 9 Months Ended
--- | ---
Sep. 30, 2021
Marketable Securities |
Marketable Securities | (4) Marketable Securities ​ The following is a summary of marketable debt securities, classified as available-for-sale: ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Gross Unrealized
​ | ​ | Amortized | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Fair
​ |  | Cost |  | Gains |  | Losses |  | Value
​ | ​ | (In thousands)
September 30, 2021 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Marketable securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. government and municipal obligations | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 24,291 | ​ | $ | 5 | ​ | $ | — | ​ | $ | 24,296
Maturing after one year through three years | ​ | ​ | 75,314 | ​ | ​ | 2 | ​ | ​ | (17) | ​ | ​ | 75,299
Total U.S. government and municipal obligations | ​ | $ | 99,605 | ​ | $ | 7 | ​ | $ | (17) | ​ | $ | 99,595
Corporate debt securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Maturing in one year or less | ​ | $ | 183,504 | ​ | $ | — | ​ | $ | (10) | ​ | $ | 183,494
Maturing after one year through three years | ​ | ​ | 67,844 | ​ | ​ | 8 | ​ | ​ | (36) | ​ | ​ | 67,816
Total corporate debt securities | ​ | $ | 251,348 | ​ | $ | 8 | ​ | $ | (46) | ​ | $ | 251,310
Total marketable securities | ​ | $ | 350,953 | ​ | $ | 15 | ​ | $ | (63) | ​ | $ | 350,905
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Gross Unrealized
​ | ​ | Amortized | ​ | ​ | ​ | ​ | ​ | ​ | ​ | Fair
​ | ​ | Cost |  | Gains |  | Losses |  | Value
​ | ​ | (In thousands)
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
​ The Company holds investment-grade marketable securities, and none were in a continuous unrealized loss position for more than twelve months as of September 30, 2021 and December 31, 2020. The unrealized losses are attributable to changes in interest rates and the Company does not believe any unrealized losses represent other-than-temporary impairments. Marketable securities include $0.8 million and $0.2 million in accrued interest at September 30, 2021 and December 31, 2020, respectively.

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 The entire disclosure for investments in certain debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -URI http://asc.fasb.org/subtopic&trid=2209399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 320 -URI http://asc.fasb.org/subtopic&trid=2324412 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 940 -SubTopic 320 -URI http://asc.fasb.org/subtopic&trid=2176304 + Details
Name: | us-gaap_InvestmentsInDebtAndMarketableEquitySecuritiesAndCertainTradingAssetsDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration