Stock-Based Compensation - Summary of Option Activity (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) $ / shares shares
Number of Options
Number of options outstanding, beginning balance (in shares) | shares	80,537
Number of options granted (in shares) | shares	418,950
Number of options exercised (in shares) | shares	0
Number of options forfeited (in shares) | shares	(5,317)
Number of options expired (in shares) | shares	(69)
Number of options outstanding, ending balance (in shares) | shares	494,101
Number of options vested or expected to vest (in shares) | shares	494,101
Number of options exercisable (in shares) | shares	396,676
Weighted Average Exercise Price
Weighted average exercise price of options outstanding, beginning of period (in usd per share) | $ / shares	$ 19.32
Weighted average exercise price of options granted (in usd per share) | $ / shares	1.71
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	18.77
Weighted average exercise price of options expired (in usd per share) | $ / shares	2,254.91
Weighted average exercise price of options outstanding, end of period (in usd per share) | $ / shares	4.08
Weighted average exercise price of options vested or expected to vest (in usd per share) | $ / shares	4.08
Weighted average exercise price of options exercisable (in usd per share) | $ / shares	$ 3.94
Weighted Average Remaining Contractual Life (in years) and Aggregate Intrinsic Value
Weighted average remaining contractual life of options exercisable (in years)	2 years 8 months 5 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