Stock-Based Compensation - Schedule of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Shares
Number of options outstanding (in shares), beginning	516,820	435,228
Number of options granted (in shares)	373,612	246,872
Number of options exercised (in shares)	0	0
Number of options expired (in shares)	(248,455)	(76,158)
Number of options forfeited (in shares)	(134,682)	(89,122)
Number of options outstanding (in shares), ending	507,295	516,820
Employee Stock Option
Weighted Average Exercise Price
Shares issuable under options exercise price per share (in dollars per share)	$ 33.40	$ 46.06
Granted, exercise price per share (in dollars per share)	3.66	14.10
Exercised, exercise price per share (in dollars per share)	0	0
Expired, exercise price per share (in dollars per share)	32,750	54,340
Forfeited, exercise price per share (in dollars per share)	8.91	23.87
Shares issuable under options exercise price per share (in dollars per share)	18.31	33.40
Employee Stock Option | Minimum
Weighted Average Exercise Price
Shares issuable under options exercise price per share (in dollars per share)	5.50	7.90
Granted, exercise price per share (in dollars per share)	0.69	5.50
Exercised, exercise price per share (in dollars per share)	0	0
Expired, exercise price per share (in dollars per share)	5.50	10.2
Forfeited, exercise price per share (in dollars per share)	2.50	6.60
Shares issuable under options exercise price per share (in dollars per share)	0.69	5.50
Employee Stock Option | Maximum
Weighted Average Exercise Price
Shares issuable under options exercise price per share (in dollars per share)	106.70	106.70
Granted, exercise price per share (in dollars per share)	4.40	18.00
Exercised, exercise price per share (in dollars per share)	0	0
Expired, exercise price per share (in dollars per share)	106.70	106.70
Forfeited, exercise price per share (in dollars per share)	88.10	86.70
Shares issuable under options exercise price per share (in dollars per share)	$ 106.70	$ 106.70