Quarterly report pursuant to Section 13 or 15(d)

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

v3.5.0.2
Description of Stock Plans - Exercise Price for Options Outstanding and Options Exercisable (Detail)
 3 Months Ended
Jun. 30, 2016
$ / shares
shares
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Options Outstanding, Number of Shares (in shares) | shares 7,912,983
Options Exercisable, Number of Shares (in shares) | shares 3,295,307
$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) 3 years 8 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 148,753
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 0.65
Options Outstanding, Weighted Average Remaining Life (Years) 6 years 22 days
Options Exercisable, Number of Shares (in shares) | shares 144,978
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 0.65
$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 2,363,975
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 1.33
Options Outstanding, Weighted Average Remaining Life (Years) 4 years 2 months 16 days
Options Exercisable, Number of Shares (in shares) | shares 46,167
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 1.25
$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 351,889
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 1.51
Options Outstanding, Weighted Average Remaining Life (Years) 9 years 4 months 6 days
Options Exercisable, Number of Shares (in shares) | shares 63,764
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) 4 years 6 months 29 days
Options Exercisable, Number of Shares (in shares) | shares 170,443
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 2.41
$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 1,190,859
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 2.62
Options Outstanding, Weighted Average Remaining Life (Years) 8 years 3 months 4 days
Options Exercisable, Number of Shares (in shares) | shares 638,634
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 2.64
$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 1,535,022
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 3.94
Options Outstanding, Weighted Average Remaining Life (Years) 8 years 4 months 28 days
Options Exercisable, Number of Shares (in shares) | shares 805,167
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 3.93
$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 1,530,644
Options Outstanding, Weighted Average Exercise Price (in usd per share) $ 4.19
Options Outstanding, Weighted Average Remaining Life (Years) 7 years 5 months 1 day
Options Exercisable, Number of Shares (in shares) | shares 916,214
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 4.23
$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) 6 years 8 months 27 days
Options Exercisable, Number of Shares (in shares) | shares 60,000
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) 2 years 6 months 4 days
Options Exercisable, Number of Shares (in shares) | shares 441,875
Options Exercisable, Weighted Average Exercise Price (in usd per share) $ 16.98