Quarterly report pursuant to Section 13 or 15(d)

Description of Stock Plans - Exercise Price for Options Outstanding and Options Exercisable (Detail)

v3.3.1.900
Description of Stock Plans - Exercise Price for Options Outstanding and Options Exercisable (Detail)
 9 Months Ended
Dec. 31, 2015
$ / shares
shares
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Options Outstanding, Number of Shares (in shares) | shares 7,841,292
Options Exercisable, Number of Shares (in shares) | shares 2,570,806
$0.00 - 0.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit $ 0
Range of Exercise Price, upper limit $ 0.50
Options Outstanding, Number of Shares (in shares) | shares 8,065
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 0.24
Options Outstanding, Weighted Average Remaining Life (Years) 4 years 2 months 27 days
Options Exercisable, Number of Shares (in shares) | shares 8,065
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 0.24
$0.51 - 1.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 0.51
Range of Exercise Price, upper limit $ 1.00
Options Outstanding, Number of Shares (in shares) | shares 168,981
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 0.65
Options Outstanding, Weighted Average Remaining Life (Years) 6 years 7 months 28 days
Options Exercisable, Number of Shares (in shares) | shares 134,058
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 0.64
$1.01 - 1.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 1.01
Range of Exercise Price, upper limit $ 1.5
Options Outstanding, Number of Shares (in shares) | shares 1,644,125
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 1.43
Options Outstanding, Weighted Average Remaining Life (Years) 7 years 9 months
Options Exercisable, Number of Shares (in shares) | shares 0
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 0.00
$1.51 - 2.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 1.51
Range of Exercise Price, upper limit $ 2
Options Outstanding, Number of Shares (in shares) | shares 440,500
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 1.51
Options Outstanding, Weighted Average Remaining Life (Years) 9 years 10 months 6 days
Options Exercisable, Number of Shares (in shares) | shares 9,514
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 1.51
$2.01 - 2.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 2.01
Range of Exercise Price, upper limit $ 2.50
Options Outstanding, Number of Shares (in shares) | shares 253,776
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 2.43
Options Outstanding, Weighted Average Remaining Life (Years) 5 years 29 days
Options Exercisable, Number of Shares (in shares) | shares 153,776
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 2.40
$2.51 - 3.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 2.51
Range of Exercise Price, upper limit $ 3.00
Options Outstanding, Number of Shares (in shares) | shares 1,283,890
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 2.62
Options Outstanding, Weighted Average Remaining Life (Years) 8 years 9 months 22 days
Options Exercisable, Number of Shares (in shares) | shares 513,551
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 2.66
$3.51 - 4.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 3.51
Range of Exercise Price, upper limit $ 4.00
Options Outstanding, Number of Shares (in shares) | shares 1,863,729
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 3.93
Options Outstanding, Weighted Average Remaining Life (Years) 8 years 11 months 9 days
Options Exercisable, Number of Shares (in shares) | shares 558,295
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 3.94
$4.01 - 4.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 4.01
Range of Exercise Price, upper limit $ 4.50
Options Outstanding, Number of Shares (in shares) | shares 1,648,226
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 4.20
Options Outstanding, Weighted Average Remaining Life (Years) 7 years 11 months 19 days
Options Exercisable, Number of Shares (in shares) | shares 702,922
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 4.22
$4.51 - 5.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit 4.51
Range of Exercise Price, upper limit $ 5.00
Options Outstanding, Number of Shares (in shares) | shares 60,000
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 4.65
Options Outstanding, Weighted Average Remaining Life (Years) 7 years 2 months 27 days
Options Exercisable, Number of Shares (in shares) | shares 55,000
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 4.65
$5.01 and over  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Exercise Price $ 5.01
Options Outstanding, Number of Shares (in shares) | shares 470,000
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 16.32
Options Outstanding, Weighted Average Remaining Life (Years) 3 years 4 days
Options Exercisable, Number of Shares (in shares) | shares 435,625
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 17.14