Share Based Awards (Details Textual) - USD ($)			3 Months Ended		6 Months Ended
	Aug. 04, 2017	Aug. 11, 2014	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2017	Aug. 31, 2015	Oct. 31, 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate			37.20%	36.90%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term			5 years 7 months	6 years 7 months
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Minimum					37.20%	36.90%
Share Based Awards (Textual) [Abstract]
Document Period End Date					Sep. 30, 2017
Outstanding options under 1998 and 2005 plan			2,692,235		2,692,235		2,885,415
Weighted-average grant date fair value per share of stock options			$ 6.11	$ 4.92
Total share-based compensation			$ 3,091,000	$ 1,918,000	$ 5,132,000	$ 3,177,000
Fair value of options vested			$ 2,092,000	$ 1,486,000
Employee Stock Purchase Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate, Maximum					37.70%	37.40%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate			0.00%	0.00%	0.00%	0.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate			1.90%	1.20%	1.90%
Employee Stock Option [Member]
Share Based Awards (Textual) [Abstract]
Total unrecognized compensation costs			$ 7,590,000		$ 7,590,000
Stock option recognized over weighted average period (in years)			3 years 1 month
Restricted Stock Units Award [Member]
Share Based Awards (Textual) [Abstract]
Total share-based compensation			$ 2,207,000	$ 972,000	3,746,000	$ 1,517,000
Total unrecognized compensation costs			$ 20,842,000		20,842,000
Stock option recognized over weighted average period (in years)			2 years 5 months
Employee Share Purchase Plan [Member]
Share Based Awards (Textual) [Abstract]
Total share-based compensation			$ 80,000	$ 81,000	$ 177,000	$ 207,000
2005 Stock Options Plan [Member]
Share Based Awards (Textual) [Abstract]
Common stock reserved									4,800,000
Outstanding options under 1998 and 2005 plan			702,860		702,860
2005 Stock Options Plan [Member] | Employee Stock Option [Member]
Share Based Awards (Textual) [Abstract]
Expiration period (in years)			10 years
Two Thousand Fifteen Stock Options Plan [Member]
Share Based Awards (Textual) [Abstract]
Common stock reserved								11,500,000
Two Thousand Fifteen Stock Options Plan [Member] | Restricted Stock Units Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					334,000
Share Based Awards (Textual) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					1,081,374
Number of Shares Outstanding			1,619,002		1,619,002		902,948
Weighted-average grant date fair value per share of stock options					$ 6.11
Amended Two Thousand Fifteen Stock Options Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross					334,000
Share Based Awards (Textual) [Abstract]
Common stock reserved	6,000,000
Outstanding options under 1998 and 2005 plan			1,989,375		1,989,375
Shares available for future grant			11,352,428		11,352,428
Amended Two Thousand Fifteen Stock Options Plan [Member] | Restricted Stock Units Award [Member]
Share Based Awards (Textual) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number			1,619,002		1,619,002
Amended Two Thousand Fifteen Stock Options Plan [Member] | Employee Stock Option [Member]
Share Based Awards (Textual) [Abstract]
Expiration period (in years)	10 years
Employee Share Purchase Plan [Member]
Employee Stock Purchase Plan [Abstract]
Shares reserved for future grant		4,000,000	3,709,351		3,709,351
Maximum percentage of gross payroll deduction		15.00%
Purchase price as a percentage of fair market value		90.00%
Maximum shares purchase in a single transaction		1,500
Maximum amount purchased in a calendar year		$ 25,000
Shares issued			290,649		290,649
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term					5 years 7 months	6 years
Employee Stock Purchase Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate						1.20%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term					5 years 8 months	6 years 7 months
Employee Stock Purchase Plan [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate						1.50%