XML 44 R35.htm IDEA: XBRL DOCUMENT
v3.21.2

Investment Securities - Summary of Cost, Gross Unrealized Holding Gains and Losses, Allowances for Credit Losses and Fair Value of Available-for-Sale Investments by Types, Maturities and Classes of Securities (Details) - USD ($) $ in Thousands | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items] |  |
Debt securities, Amortized Cost | $ 36,060 | $ 33,556
Debt securities, Unrealized Gains | 1 | 156
Debt securities, Unrealized Losses | (5) |
Debt securities, Estimated Fair Value | $ 36,056 | $ 33,712
Certificates of deposit | Within 1 Year |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Debt securities, Maturity | Within 1 year | Within 1 year
Debt securities, Amortized Cost | $ 2,853 | $ 1,750
Debt securities, Unrealized Gains |  | 4
Debt securities, Unrealized Losses | (1) |
Debt securities, Estimated Fair Value | $ 2,852 | $ 1,754
Certificates of deposit | 1 Year to 2 Years |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Debt securities, Maturity | 1 year to 2 years |
Debt securities, Amortized Cost | $ 3,137 |
Debt securities, Unrealized Losses | (2) |
Debt securities, Estimated Fair Value | $ 3,135 |
U.S. Treasury securities | Within 1 Year |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Debt securities, Maturity | Within 1 year | Within 1 year
Debt securities, Amortized Cost | $ 10,066 | $ 31,806
Debt securities, Unrealized Gains | 1 | 152
Debt securities, Estimated Fair Value | $ 10,067 | $ 31,958
U.S. Treasury securities | 1 Year to 2 Years |  |
Schedule Of Available For Sale Securities [Line Items] |  |
Debt securities, Maturity | 1 year to 2 years |
Debt securities, Amortized Cost | $ 20,004 |
Debt securities, Unrealized Losses | (2) |
Debt securities, Estimated Fair Value | $ 20,002 |

X
- Definition Debt securities, available-for-sale, maturity. + References No definition available. + Details
Name: | dsgn_DebtSecuritiesAvailableForSaleMaturity
Namespace Prefix: | dsgn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26626-111562 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecuritiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExtinguishmentOfDebtAxis=dsgn_WithinOneYearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ExtinguishmentOfDebtAxis=dsgn_OneYearToTwoYearsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |