Annual report pursuant to Section 13 and 15(d)

NET INCOME (LOSS) PER SHARE - Anti-dilutive shares excluded from the computations of diluted net income (loss) (Details) (Details)

v3.7.0.1
NET INCOME (LOSS) PER SHARE - Anti-dilutive shares excluded from the computations of diluted net income (loss) (Details) (Details) - USD ($)
shares in Millions, $ in Millions
 12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2012
Stock options          
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Weighted average shares excluded (shares) 0.2 0.6 0.3    
Unvested restricted stock units          
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Weighted average shares excluded (shares) 0.4 1.5 0.0    
4.50% convertible subordinated notes          
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Weighted average shares excluded (shares) 5.1 5.3 5.3    
Interest expense excluded $ 0.4 $ 0.5 $ 0.5    
Stated interest rate (as a percent) 4.50%     4.50% 4.50%
3.50% convertible subordinated notes          
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]          
Weighted average shares excluded (shares) 0.0 1.3 3.6    
Interest expense excluded $ 0.0 $ 0.2 $ 0.7    
Stated interest rate (as a percent) 3.50%   3.50%