Stockholders’ Equity - Narrative (Details)	6 Months Ended	66 Months Ended
	Mar. 31, 2018 item shares	Mar. 31, 2018 shares
RSUs
Stockholders' Equity
Number of units awarded (in shares)		2,250,593
Number of shares of common stock that each award holder has the contingent right to receive	1
Vested awards to date	623,994	623,994
Expected awards vested (in shares)	420,182
Time-based RSUs
Stockholders' Equity
Number of units awarded (in shares)		1,078,129
Number of equal installments for vesting of stock awards | item	4
Performance-based RSUs
Stockholders' Equity
Number of units awarded (in shares)		1,172,464
Vesting period	3 years
Number of vesting criteria which have to be satisfied out of total vesting criteria | item	1
Number of vesting criteria | item	3