Annual report pursuant to Section 13 and 15(d)

Stock Compensation Plans (Additional Information) (Details)

v3.6.0.2
Stock Compensation Plans (Additional Information) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Issuance of common stock $ 3,061 $ 2,016 $ 3,282
Granted (in shares) 2,000,000    
Exercise limitation period 10 years    
Total compensation cost not yet recognized, stock options $ 8,716    
Unrecognized compensation cost for stock based compensation, period of recognition 2 years 2 months 19 days    
Options, exercises in period, total intrinsic value $ 6,556 2,595 4,640
Fair value of stock vested   1,197  
Allocated share-based compensation expense $ 5,311 $ 8,759 $ 10,541
Qualified Employee Stock Purchase Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares available for grant (in shares) 10,000,000    
Offering date (percent) 5.00%    
Stock issued during period, gross (in shares) 210,330 192,978 89,581
Shares authorized under stock option plans, exercise price range, lower range limit (in USD per share) $ 2.19 $ 2.00 $ 2.87
Shares authorized under stock option plans, exercise price range, upper range limit (in USD per share) $ 2.38 $ 3.67 $ 4.03
Issuance of common stock $ 481 $ 545 $ 291
Plan 1999      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares available for grant (in shares) 2,314,206    
Granted (in shares) 25,000,000    
Exercise limitation period based on voting power 5 years    
Plan 1999 | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards with annual limit (in shares) 1,500,000   1,500,000
Plan 2009      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares available for grant (in shares) 17,716,165    
Granted (in shares) 1,330,000    
Combined voting power (percent) 10.00%    
Fair market value (percent) 100.00%    
Fair market value for ten percent shareholder (percent) 110.00%    
Plan 2009 | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Granted (in shares)     45,000,000
Employees and Director Option      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options, grants in period, weighted average grant date fair value (in USD per share) $ 1.07 $ 2.79 $ 1.85
Restricted Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting period 4 years