Business Combination - Additional Information (Detail) - USD ($)
 12 Months Ended
Jun. 22, 2021
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Jun. 30, 2021
Dec. 31, 2018
Business Acquisition [Line Items]            
Common stock, par value   $ 0.0001 $ 0.0001      
Preferred stock, par value   $ 0.0001        
Conversion Of Stock, Conversion Rate $ 1.134140          
Payments to Acquire Businesses, Gross   $ 0 $ 10,685,000 $ 0    
Common stock, shares outstanding 152,255,736 152,862,447 13,413,431      
Class of Warrant or Right, Outstanding 33,480,000          
Common stock, shares authorized   1,000,000,000 129,397,278      
Preferred stock, shares authorized   100,000,000        
Conversion of Stock, Description Each whole Warrant entitles the registered holder to purchase one share of the Company’s common stock at a price of $11.50 per share, at any time commencing 30 days after the closing of the Business Combination.          
Warrants And Rights Outstanding Expiration Period 5 years          
Redemption Trigger Share Price $ 18.00          
Class of Warrant or Right Minimum Notice Period For Redemption 30 days          
Class of Warrant or Right Redemption Threshold Consecutive Trading Days 30 days          
Warrant liabilities   $ 4,070,000        
Public Warrants            
Business Acquisition [Line Items]            
Class of Warrant or Right, Outstanding 20,700,000          
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 0.01          
Class of Warrant or Right Redemption Threshold Consecutive Trading Days 20 days          
Proceeds from issuance of warrants   27,900,000        
Private Placement Warrants            
Business Acquisition [Line Items]            
Class of Warrant or Right, Outstanding         10,280,000  
Class of warrant or right issued during the period 2,500,000          
Warrant liabilities   $ 4,100,000        
Common Stock [Member]            
Business Acquisition [Line Items]            
Common stock, shares outstanding   152,862,447 13,413,431 13,223,672   11,713,491
Old Talkspace            
Business Acquisition [Line Items]            
Business Acquisition, Date of Acquisition Agreement   Jan. 12, 2021        
Payments for Repurchase of Common Stock $ 199,300          
Conversion of Stock, Shares Converted 109,461,534          
Converted Stock, Deemed Value Per Share         $ 10.00  
Conversion of Stock, Shares Issued 91,473,779          
Conversion of Stock, Shares Options 17,987,755          
Conversion Of Stock, Conversion Rate $ 1.134140          
Old Talkspace | Common Stock [Member]            
Business Acquisition [Line Items]            
Common stock, par value $ 0.001          
Old Talkspace | Seed Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Seed One Convertible Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Seed Two Convertible Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Series A Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Series B Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Series C Preferred Stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Old Talkspace | Preferred D stock            
Business Acquisition [Line Items]            
Preferred stock, par value         0.001  
Talkspace | Common Stock [Member]            
Business Acquisition [Line Items]            
Common stock, par value         $ 0.0001  
Pipe Investors | Subscription Agreement            
Business Acquisition [Line Items]            
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares 30,000,000          
Shares Issued, Price Per Share $ 10.00          
Payments to Acquire Businesses, Gross $ 300,000.0          
Hec Master Fund Lp | Forward Contracts            
Business Acquisition [Line Items]            
Redemption Amount From Forward Purchase 25,000.0          
Hec Master Fund Lp | Forward Contracts | Private Placement            
Business Acquisition [Line Items]            
Forward Purchase Amount $ 25,000.0          
Hec Master Fund Lp | Common Class A            
Business Acquisition [Line Items]            
Redemption of Stock 25,968,043          
Hec Master Fund Lp | Common Class A | Forward Contracts            
Business Acquisition [Line Items]            
Common stock, par value $ 10.00          
Forward Purchase Unit 2,500,000