Stockholders' Equity - Warrants Outstanding by Expiration Date (Details) - $ / shares	Sep. 30, 2016	Jul. 23, 2015
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	2,317,847
February 2017
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	246,914
Exercise price (in dollars per share)	$ 52.5
May 2018
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	300,000
Exercise price (in dollars per share)	$ 34
January 2023
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	428,621
Exercise price (in dollars per share)	$ 8.8
March 2023
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	441,763
Exercise price (in dollars per share)	$ 8.8
October 2024
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	19,380
Exercise price (in dollars per share)	$ 12.9
July 2025
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	15,244	15,244
Exercise price (in dollars per share)	$ 16.4	$ 16.40
March 2022
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	811,802
Exercise price (in dollars per share)	$ 4.5
September 2021
Class of Warrant or Right [Line Items]
Shares issuable upon exercise (in shares)	54,123
Exercise price (in dollars per share)	$ 4.3125