Annual report pursuant to Section 13 and 15(d)

STOCKHOLDERS' EQUITY - Narrative (Details)

v3.19.1
STOCKHOLDERS' EQUITY - Narrative (Details)
 6 Months Ended 12 Months Ended
Feb. 01, 2018
USD ($)
shares
Jan. 24, 2017
USD ($)
shares
Jun. 30, 2017
class
Dec. 31, 2018
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
$ / shares
shares
Apr. 07, 2016
shares
Jan. 12, 2016
USD ($)
Jul. 28, 2015
USD ($)
Class of Stock [Line Items]                
Number of classes of stock | class     2          
Preferred stock, shares authorized (in shares)       5,000,000 5,000,000      
Preferred stock, par value (in dollars per share) | $ / shares       $ 0.001 $ 0.001      
Common stock, shares authorized (in shares)       50,000,000 50,000,000      
Common stock, par value (in dollars per share) | $ / shares       $ 0.001 $ 0.001      
Authorized amount of shares to be repurchased | $             $ 70,000,000.0 $ 15,000,000.0
Repurchase of common stock (in shares)       0 0      
Remaining authorized repurchase amount | $       $ 32,000,000.0        
Restricted Stock                
Class of Stock [Line Items]                
Stock-based compensation expense recognized | $       $ 0 $ 35,000      
2016 Plan | Restricted Stock                
Class of Stock [Line Items]                
Number of shares granted (in shares) 34,202 56,260   34,202 56,260      
Shares vesting period 3 years 3 years            
Value of shares granted | $ $ 554,000 $ 1,400,000            
Common Stock | 2016 Plan                
Class of Stock [Line Items]                
Number of shares authorized (in shares)           2,500,000    
Number of shares available for issuance (in shares)       2,359,671