Annual report pursuant to Section 13 and 15(d)

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

v3.7.0.1
Description of Stock Plans - Exercise Price for Options Outstanding and Options Exercisable (Detail)
 12 Months Ended
Mar. 31, 2017
$ / shares
shares
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Options Outstanding (in shares) | shares 9,735,778
Options Exercisable (in shares) | shares 3,557,304
$0.00 - 0.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) $ 0
Range of Exercise Price, upper limit ($ per share) $ 0.50
Options Outstanding (in shares) | shares 7,652
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 0.24
Weighted-Average Remaining Life (Years) 2 years 11 months 27 days
Options Exercisable (in shares) | shares 7,652
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 0.24
$0.51 - 1.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 0.51
Range of Exercise Price, upper limit ($ per share) $ 1.00
Options Outstanding (in shares) | shares 3,286,153
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 0.70
Weighted-Average Remaining Life (Years) 9 years 5 months 27 days
Options Exercisable (in shares) | shares 184,995
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 0.66
$1.01 - 1.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 1.01
Range of Exercise Price, upper limit ($ per share) $ 1.5
Options Outstanding (in shares) | shares 2,501,351
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 1.32
Weighted-Average Remaining Life (Years) 8 years 11 months 19 days
Options Exercisable (in shares) | shares 333,315
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 1.24
$1.51 - 2.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 1.51
Range of Exercise Price, upper limit ($ per share) $ 2
Options Outstanding (in shares) | shares 223,834
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 1.51
Weighted-Average Remaining Life (Years) 8 years 1 month 2 days
Options Exercisable (in shares) | shares 101,000
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 1.51
$2.01 - 2.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 2.01
Range of Exercise Price, upper limit ($ per share) $ 2.50
Options Outstanding (in shares) | shares 253,779
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 2.43
Weighted-Average Remaining Life (Years) 3 years 9 months 29 days
Options Exercisable (in shares) | shares 203,779
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 2.42
$2.51 - 3.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 2.51
Range of Exercise Price, upper limit ($ per share) $ 3.00
Options Outstanding (in shares) | shares 994,616
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 2.61
Weighted-Average Remaining Life (Years) 7 years 1 month 24 days
Options Exercisable (in shares) | shares 758,799
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 2.63
$3.51 - 4.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 3.51
Range of Exercise Price, upper limit ($ per share) $ 4.00
Options Outstanding (in shares) | shares 1,062,661
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 3.95
Weighted-Average Remaining Life (Years) 6 years 9 months 7 days
Options Exercisable (in shares) | shares 792,893
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 3.95
$4.01 - 4.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 4.01
Range of Exercise Price, upper limit ($ per share) $ 4.50
Options Outstanding (in shares) | shares 875,732
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 4.14
Weighted-Average Remaining Life (Years) 6 years 2 months 19 days
Options Exercisable (in shares) | shares 663,621
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 4.14
$4.51 - 5.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of Exercise Price, lower limit ($ per share) 4.51
Range of Exercise Price, upper limit ($ per share) $ 5.00
Options Outstanding (in shares) | shares 60,000
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 4.65
Weighted-Average Remaining Life (Years) 5 years 11 months 27 days
Options Exercisable (in shares) | shares 60,000
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 4.65
$5.01 and over  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Exercise Price ($ per share) $ 5.01
Options Outstanding (in shares) | shares 470,000
Options Outstanding, Weighted Average Exercise Price ($ per share) $ 16.32
Weighted-Average Remaining Life (Years) 1 year 9 months 4 days
Options Exercisable (in shares) | shares 451,250
Options Exercisable, Weighted Average Exercise Price ($ per share) $ 16.75