Quarterly report pursuant to Section 13 or 15(d)

Description of Stock Plans - Summary of Exercise Price (Details)

v3.19.2
Description of Stock Plans - Summary of Exercise Price (Details)
 3 Months Ended
Jun. 30, 2019
$ / shares
shares
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Options Outstanding, Number of Shares (in shares) | shares 9,624,007
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 2.13
Options Outstanding, Weighted Average Remaining Life 7 years 5 months
Options Exercisable, Number of Shares (in shares) | shares 5,507,764
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 2.10
$0.00 - 0.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 0
Range of exercise price, upper limit (in dollars per share) $ 0.50
Options Outstanding, Number of Shares (in shares) | shares 6,204
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 0.24
Options Outstanding, Weighted Average Remaining Life 8 months 25 days
Options Exercisable, Number of Shares (in shares) | shares 6,204
Options Exercisable, Weighted Average Exercise Price (in dollars 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 (in dollars per share) 0.51
Range of exercise price, upper limit (in dollars per share) $ 1.00
Options Outstanding, Number of Shares (in shares) | shares 2,003,836
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 0.73
Options Outstanding, Weighted Average Remaining Life 7 years 3 months
Options Exercisable, Number of Shares (in shares) | shares 1,069,970
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 0.72
$1.01 - 1.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 1.01
Range of exercise price, upper limit (in dollars per share) $ 1.5
Options Outstanding, Number of Shares (in shares) | shares 2,339,589
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 1.29
Options Outstanding, Weighted Average Remaining Life 7 years 15 days
Options Exercisable, Number of Shares (in shares) | shares 1,668,139
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 1.27
$1.51 - 2.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 1.51
Range of exercise price, upper limit (in dollars per share) $ 2
Options Outstanding, Number of Shares (in shares) | shares 1,239,097
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 1.66
Options Outstanding, Weighted Average Remaining Life 8 years 7 months 16 days
Options Exercisable, Number of Shares (in shares) | shares 499,602
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 1.63
$2.01 - 2.50  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 2.01
Range of exercise price, upper limit (in dollars per share) $ 2.50
Options Outstanding, Number of Shares (in shares) | shares 655,392
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 2.21
Options Outstanding, Weighted Average Remaining Life 8 years 8 months 15 days
Options Exercisable, Number of Shares (in shares) | shares 229,680
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 2.17
$2.51 - 3.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 2.51
Range of exercise price, upper limit (in dollars per share) $ 3.00
Options Outstanding, Number of Shares (in shares) | shares 690,100
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 2.61
Options Outstanding, Weighted Average Remaining Life 4 years 11 months 17 days
Options Exercisable, Number of Shares (in shares) | shares 690,100
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 2.61
$3.51 - 4.00  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Range of exercise price, lower limit (in dollars per share) 3.51
Range of exercise price, upper limit (in dollars per share) $ 4.00
Options Outstanding, Number of Shares (in shares) | shares 2,034,789
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 3.89
Options Outstanding, Weighted Average Remaining Life 8 years 4 months 30 days
Options Exercisable, Number of Shares (in shares) | shares 689,069
Options Exercisable, Weighted Average Exercise Price (in dollars 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 (in dollars per share) 4.01
Range of exercise price, upper limit (in dollars per share) $ 4.50
Options Outstanding, Number of Shares (in shares) | shares 545,000
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 4.14
Options Outstanding, Weighted Average Remaining Life 5 years 4 months 2 days
Options Exercisable, Number of Shares (in shares) | shares 545,000
Options Exercisable, Weighted Average Exercise Price (in dollars 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 (in dollars per share) 4.51
Range of exercise price, upper limit (in dollars per share) $ 5.00
Options Outstanding, Number of Shares (in shares) | shares 60,000
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 4.65
Options Outstanding, Weighted Average Remaining Life 3 years 8 months 25 days
Options Exercisable, Number of Shares (in shares) | shares 60,000
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 4.65
$5.01 and over  
Employee Stock Ownership Plan E S O P Disclosures [Line Items]  
Exercise price (in dollars per share) $ 5.01
Options Outstanding, Number of Shares (in shares) | shares 50,000
Options Outstanding, Weighted Average Exercise Price (in dollars per share) $ 5.89
Options Outstanding, Weighted Average Remaining Life 5 years 2 months 12 days
Options Exercisable, Number of Shares (in shares) | shares 50,000
Options Exercisable, Weighted Average Exercise Price (in dollars per share) $ 5.89