Net Loss Per Share Attributable to Common Stockholders - Summary of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Earnings Per Share [Abstract]      
Net loss $ 62,742 $ 22,370 $ 29,086
Weighted-average shares used to compute net loss per share, basic and diluted [1] 86,775,948 13,359,350 12,721,426
Net loss per share, basic and diluted [1] $ 0.72 $ 1.67 $ 2.29
[1] Prior period results have been adjusted to reflect the exchange of Old Talkspace’s common stock for Talkspace’s common stock at an exchange ratio of approximately 1.134140 in June 2021 as a result of the Business Combination. See Note 3, “Business Combination” in the notes to the consolidated financial statements for further details.