Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity and Stock Based Compensation - Vesting (Details)

v3.8.0.1
Stockholders' Equity and Stock Based Compensation - Vesting (Details)
9 Months Ended 12 Months Ended
Sep. 30, 2017
installment
shares
Dec. 31, 2016
installment
shares
Dec. 31, 2015
installment
shares
Dec. 31, 2014
installment
shares
Dec. 31, 2013
installment
shares
Dec. 31, 2012
installment
shares
Stock-based compensation            
Number of shares of common stock initially available for award 600,000          
Options reserved for future issuance (in shares) 226,788          
Restricted stock            
Stock-based compensation            
Granted (in shares) 87,076 171,252 44,000 98,689 56,500 92,000
Number of equal quarterly installments for vesting of awards | installment     16   20 20
Forfeited (in shares) 3,636 7,167 4,465 34,487 775 3,525
Restricted stock | Minimum            
Stock-based compensation            
Number of equal quarterly installments for vesting of awards | installment 8 1   1    
Restricted stock | Maximum            
Stock-based compensation            
Number of equal quarterly installments for vesting of awards | installment 20 20   20    
Restricted stock | CEO            
Stock-based compensation            
Granted (in shares)         40,000  
Number of equal quarterly installments for vesting of awards | installment         16