Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Details Textual)

v3.19.2
Stockholders' Equity (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Nov. 01, 2018
Sep. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
May 22, 2015
Stockholders' Equity (Textual)                  
Number of shares issued       2,640,819          
Shares issued price per share (in dollars per share)       $ 5.50 $ 5.00   $ 5.00    
Proceeds from issuance of shares       $ 14,500          
Stock commissions and expenses       $ 1,300          
Terms of Award             (generally vesting either ratably over the first four years or on a tier basis of 50% on the second anniversary of the effective date and 25% on the third and fourth anniversary dates).    
Stock based compensation             $ 7,240 $ 5,491  
Placement Agent Warrants [Member]                  
Stockholders' Equity (Textual)                  
Grant date fair value             $ 646    
Warrants to purchase             154,177    
Investors [Member] | Placement Agent Warrants [Member]                  
Stockholders' Equity (Textual)                  
Number of shares issued               542,450  
One investor [Member]                  
Stockholders' Equity (Textual)                  
Shares issued price per share (in dollars per share)         $ 4.40   $ 4.40    
October 2018 Offering [Member]                  
Stockholders' Equity (Textual)                  
Shares issued price per share (in dollars per share)     $ 4.25            
Sale of stock     7,250            
Offering expenses payable     $ 2,100            
Aggregate gross proceeds     $ 30,800            
October 2018 Offering [Member] | Investors [Member]                  
Stockholders' Equity (Textual)                  
Number of shares issued             113,592    
Terms of Award             In the case of an Incentive Stock Option that is granted to a 10% shareholder on the date of grant, such Option shall not be exercisable after the expiration of five years from the date of grant.      
Employee Stock Purchase Plan [Member]                  
Stockholders' Equity (Textual)                  
Stock based compensation         $ 40 $ 0      
Issued shares under the ESPP         0.02 0.0      
Future issuance of shares under this plan         0.48        
Acquire common stock in percent 85.00%                
Equity incentive plans [Member]                  
Stockholders' Equity (Textual)                  
Number of stock authorized                 1,200,000
Total intrinsic value of options exercisable         $ 20 $ 0 $ 20 $ 0  
Unrecognized stock based compensation expense         2,800   $ 2,800    
Unrecognized stock based compensation expense amortized period             2 years    
Stock based compensation             $ 2,300 1,700  
Performance Awards [Member]                  
Stockholders' Equity (Textual)                  
Grant date fair value   $ 119,500              
Unrecognized stock based compensation expense         177   177    
Stock based compensation             $ 630 $ 30  
Weighted average exercise price             $ 8.30 $ 6.26  
Total vested fair value         $ 100 0 $ 100 $ 0  
Award nonvested (in shares)         120   120    
Award exercises in period             119    
Restricted Stock Units and Restricted Stock Awards [Member]                  
Stockholders' Equity (Textual)                  
Unrecognized stock based compensation expense         $ 4,200   $ 4,200    
Stock based compensation             $ 4,200 $ 3,800  
Weighted average exercise price             $ 6.21 $ 6.61  
Total vested fair value         $ 4,900 $ 3,800 $ 4,900 $ 3,800