Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Parenthetical) (Detail) - $ / shares	Jun. 30, 2021	Jun. 22, 2021
Earnings Per Share [Abstract]
Conversion of stock, conversion rate	$ 1.134140	$ 1.134140

The exchange rate per share of the conversion feature embedded in the business combination.

No definition available.

Name:	talk_ConversionOfStockConversionRate
Namespace Prefix:	talk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant