Quarterly report pursuant to Section 13 or 15(d)

Debt - Senior Convertible Notes, net (Details)

v3.10.0.1
Debt - Senior Convertible Notes, net (Details)
$ / shares in Units, shares in Millions
1 Months Ended 3 Months Ended 9 Months Ended
Feb. 28, 2017
USD ($)
Mar. 18, 2016
Nov. 03, 2014
USD ($)
$ / shares
Mar. 31, 2017
USD ($)
$ / shares
shares
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Mar. 31, 2017
USD ($)
$ / shares
shares
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Debt Instrument [Line Items]                  
Net proceeds from offering               $ 0 $ 95,140,000
Payment for indenture consent $ 1,600,000                
Debt conversion amount               0 4,912,000
Debt conversion expense         $ 0 $ 0 $ 1,200,000 0 $ 1,209,000
Common Shares                  
Debt Instrument [Line Items]                  
Debt conversion expense (in shares) | shares             0.2    
Convertible Senior Notes Due 2019                  
Debt Instrument [Line Items]                  
Aggregate principal amount     $ 200,000,000.0   $ 18,600,000     $ 18,600,000  
Interest rate     7.50%            
Additional aggregate principal amount pertaining to the over-allotment option granted     $ 25,000,000.0            
Net proceeds from offering     $ 187,300,000            
Conversion rate (per $1,000 principal amount of notes)   0.3215434              
Conversion price (in dollars per share) | $ / shares     $ 3.11 $ 3.11     $ 3.11    
Transactions costs     $ 12,700,000            
Debt conversion amount       $ 4,900,000          
Number of shares issued on conversion of debt (in shares) | shares       1.8          
Debt conversion per original conversion price (in shares) | shares       1.6