Debt instrument covenant compliance, revenue target.

No definition available.

Name:	ttoo_DebtInstrumentCovenantComplianceRevenueTarget
Namespace Prefix:	ttoo_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Contractual deferred interest rate during interest only payments for funds borrowed, under the debt agreement.

+ References

No definition available.

+ Details

Name:	ttoo_DebtInstrumentDeferredInterestRateInterestOnlyPayment
Namespace Prefix:	ttoo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Additional interest rate on all outstanding obligations during the occurrence and continuance of an event of default.

+ References

No definition available.

+ Details

Name:	ttoo_DebtInstrumentEventOfDefaultAdditionalInterestRate
Namespace Prefix:	ttoo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Final fee as a percentage of the amount of principal outstanding upon repayment.

+ References

No definition available.

+ Details

Name:	ttoo_DebtInstrumentFinalPaymentFeePercentage
Namespace Prefix:	ttoo_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Prepayment fee period of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	ttoo_DebtInstrumentPrepaymentFeeTerm
Namespace Prefix:	ttoo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument of interest only payments, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	ttoo_DebtInstrumentTermOfInterestOnlyPayments
Namespace Prefix:	ttoo_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Name:	us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

+ References

+ Details

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of the required periodic payments applied to principal.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfLongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=ttoo_CRGMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ttoo_TermLoanAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=srt_ScenarioForecastMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=ttoo_TermLoanAgreementAmendedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Notes Payable - Term Loan Agreement - Additional Information (Detail) - USD ($)	1 Months Ended			9 Months Ended		24 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2016	Dec. 31, 2022	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Common Stock [Member]
Debt Instrument
Number of shares issuable for warrants outstanding (in shares)	568,291		528,958
Exercise price of warrants	$ 1.55	$ 4.35	$ 8.06
CRG [Member] \| Term Loan Agreement [Member]
Debt Instrument
Proceeds from issuance of long-term debt			$ 40,000,000.0
Debt term (in years)			6 years
Debt instrument, term of interest-only payments (in years)			4 years
Final fee as a percentage of the principal outstanding (as a percent)	10.00%		8.00%		10.00%
Annual fixed rate (as a percent)			11.50%
Deferred interest rate (as a percent)			3.50%
Debt instrument, prepayment fee term (in years)			5 years
Debt instrument covenant compliance revenue target	$ 4,000,000	$ 9,000,000.0
Additional interest rate, event of default (as a percent)					4.00%
CRG [Member] \| Term Loan Agreement [Member] \| Scenario Forecast [Member]
Debt Instrument
Debt instrument, quarterly principal payment				$ 12,000,000.0
Debt instrument covenant compliance revenue target						$ 140,000,000	$ 95,000,000
CRG [Member] \| Term Loan Agreement, Amended [Member] \| Scenario Forecast [Member]
Debt Instrument
Debt instrument covenant compliance revenue target						$ 43,000,000	$ 15,000,000