Share-based Compensation - Summary of stock options outstanding (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Grant date fair value of stock options vested	$ 963,205	$ 963,205
Intrinsic value of stock options exercised	$ 219,813

Share-based Compensation Arrangement by Share-based Payment Award, Stock Options, Vested, Weighted Average Grant Date Fair Value

No definition available.

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Namespace Prefix:	thrn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration