Equity (Schedule of Common Stock Reserved for Future Issuances) (Details) - shares	Jun. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise of outstanding stock options (in shares)	448,481	750,338
Purchases under the employee stock purchase plan (in shares)	973,322
Issuance of stock-based awards under the Equity Plans (in shares)	2,725,158
Purchases under the officer and director share purchase plan (in shares)	88,741
Total reserved (in shares)	5,398,408
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	800,665	878,416
Performance stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested stock units (in shares)	362,041	0