Stock-Based Compensation - Summary of Option Activity (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) $ / shares shares
Number of Options
Number of options outstanding, beginning balance (in shares) | shares	97,891
Number of options granted (in shares) | shares	6,488
Number of options exercised (in shares) | shares	0
Number of options forfeited (in shares) | shares	(23,825)
Number of options expired (in shares) | shares	(17)
Number of options outstanding, ending balance (in shares) | shares	80,537
Number of options vested or expected to vest (in shares) | shares	80,537
Number of options exercisable (in shares) | shares	25,388
Weighted Average Exercise Price
Weighted average exercise price of options outstanding, beginning of period (in usd per share) | $ / shares	$ 37.95
Weighted average exercise price of options granted (in usd per share) | $ / shares	2.37
Weighted average exercise price of options exercised (in usd per share) | $ / shares	0
Weighted average exercise price of options forfeited (in usd per share) | $ / shares	83.27
Weighted average exercise price of options expired (in usd per share) | $ / shares	11,187.28
Weighted average exercise price of options outstanding, end of period (in usd per share) | $ / shares	19.32
Weighted average exercise price of options vested or expected to vest (in usd per share) | $ / shares	19.32
Weighted average exercise price of options exercisable (in usd per share) | $ / shares	$ 37.26
Weighted Average Remaining Contractual Life (in years) and Aggregate Intrinsic Value
Weighted average remaining contractual life of options outstanding (in years)	8 years 7 months 6 days
Weighted average remaining contractual life of options vested or expected to vest (in years)	8 years 7 months 6 days
Weighted average remaining contractual life of options exercisable (in years)	8 years 3 months 18 days
Aggregate intrinsic value of options outstanding | $	$ 0
Aggregate intrinsic value of options vested and expected to vest | $	0
Aggregate intrinsic value of options exercisable | $	$ 0