Quarterly report pursuant to Section 13 or 15(d)

Note 1 - Nature of Operations and Summary of Significant Accounting Policies - Clinics in Operation Under Franchise Agreements or Company-owned or Managed (Details)

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Note 1 - Nature of Operations and Summary of Significant Accounting Policies - Clinics in Operation Under Franchise Agreements or Company-owned or Managed (Details)
 3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2019
Mar. 31, 2018
Clinics in operation at the end of the period 454 406    
Total clinics in operation at the end of the period 454 406 454 406
Clinic licenses sold but not yet developed     145 114
Executed letters of intent for future clinic licenses     27 8
Franchised Units [Member]        
Clinics open at beginning of period 394 352    
Opened or Purchased during the period 12 7    
Acquired or sold during the period (1)    
Closed during the period (1)    
Clinics in operation at the end of the period 404 359    
Opened during the period 12 7    
Acquired during the period 1    
Closed or Sold during the period (1)    
Total clinics in operation at the end of the period 394 352 404 359
Entity Operated Units [Member]        
Clinics open at beginning of period 48 47    
Opened or Purchased during the period 2    
Acquired or sold during the period (1)    
Closed during the period (1)    
Clinics in operation at the end of the period 50 47    
Opened during the period 2    
Acquired during the period 1    
Closed or Sold during the period (1)    
Total clinics in operation at the end of the period 48 47 50 47