Share-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 22, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of stock options	[1]					3,302,831
Stock option award granted	[1]					1,013,759
Total unrecognized compensation cost non-vested options to be recognized, period						4 years
Conversion of stock, conversion rate		$ 1.134140				$ 1.134140		$ 1.134140
Warrants issued		650,000				650,000
Share based compensation expense		$ 15,196		$ 332		$ 16,709	$ 733
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value						$ 6.33	$ 0.90
Total unrecognized compensation cost, non-vested options		$ 18,300				$ 18,300
Share-based Payment Arrangement, Plan Modification, Incremental Cost						5,200
Share based compensation expense						$ 12,300
2021 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance		15,565,074				15,565,074
2021 Employee Stock Purchase Plan | Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option award granted		317,010
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of stock options	[2]	2,617,908	684,923	29,516	122,004
Common stock | 2021 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares to be issued in connection with stock option exercises under plan		100,000,000				100,000,000
Common stock | 2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares reserved for issuance		2,983,015				2,983,015
Common stock | Maximum [Member] | 2021 Incentive Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum increase in annual amount number of common stock shares outstanding percentage						5.00%
Common stock | Maximum [Member] | 2021 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum increase in annual amount number of common stock shares outstanding percentage						1.00%
Maximum number of shares granted		50,000,000				50,000,000

[1] Number of options and the weighted average exercise price 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,” for further details.

[2] (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,” for further details.