XML 44 R33.htm IDEA: XBRL DOCUMENT v3.21.1

Loans Payable - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended
	Dec. 31, 2020	May 31, 2020	Mar. 31, 2021	Dec. 29, 2020	Oct. 31, 2018	Apr. 30, 2017
Short Term Debt [Line Items]
Debt Instrument, fair value			$ 0
Convertible preferred stock, shares issued	12,958,452		0
Bridge Loan
Short Term Debt [Line Items]
Debt Instrument, fair value	$ 2,100
Proceeds from issuance of debt		$ 1,800
Debt instrument, interest rate		10.00%
Debt conversion, original debt, amount	1,800
Proceeds from debt payable in different currency, description			payable in renminbi (RMB) at an established USD/RMB exchange rate, based on an average of the previous five working days before May 8, 2020.
Debt conversion to stock, aggregate debt plus accrued interest	$ 1,900
Debt conversion, accrued interest, amount				$ 100
Series C convertible preferred stock
Short Term Debt [Line Items]
Debt conversion, converted instrument, shares		1,366,820
Convertible preferred stock, shares issued	7,500,665
Series C convertible preferred stock | Bridge Loan
Short Term Debt [Line Items]
Debt conversion, converted instrument, shares	167,159
Series A convertible preferred stock
Short Term Debt [Line Items]
Convertible preferred stock, shares issued	2,857,142					2,089,285
Series A convertible preferred stock | LAV Affiliate
Short Term Debt [Line Items]
Convertible preferred stock, shares issued	767,857
Series B convertible preferred stock
Short Term Debt [Line Items]
Convertible preferred stock, shares issued	2,600,645				2,384,195
Series B convertible preferred stock | LAV Affiliate
Short Term Debt [Line Items]
Convertible preferred stock, shares issued	216,450
2020 Notes
Short Term Debt [Line Items]
Proceeds from issuance of debt		$ 15,000
Debt instrument, interest rate		10.00%
Debt conversion, original debt, amount		$ 15,900
Debt conversion to stock, aggregate debt plus accrued interest	$ 15,900
2020 Notes | Series C convertible preferred stock
Short Term Debt [Line Items]
Debt conversion, converted instrument, shares	1,366,820

X

- Definition

Debt conversion, accrued interest on debt, amount.

+ References

No definition available.

+ Details

Name:	tern_DebtConversionAccruedInterestOnDebtAmount
Namespace Prefix:	tern_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Proceeds from debt payable in different currency, description.

+ References

No definition available.

+ Details

Name:	tern_ProceedsFromDebtPayableInDifferentCurrencyDescription
Namespace Prefix:	tern_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586

+ Details

Name:	us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The amount of the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121583591&loc=d3e4332-108586

+ Details

Name:	us-gaap_DebtConversionOriginalDebtAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- 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

X

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-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_ProceedsFromIssuanceOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

X

- Definition

The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ 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(27)(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_BridgeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=tern_SeriesCConvertiblePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=tern_SeriesAConvertiblePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_CounterpartyNameAxis=tern_LillyAsiaVenturesAffiliateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementClassOfStockAxis=tern_SeriesBConvertiblePreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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