Stockholders' Equity - Summary of Restricted Stock Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 2.54	$ 3.37	$ 6.34
Granted (in dollars per share)	0.62	2.38	3.18
Vested (in dollars per share)	2.23	3.11	5.78
Canceled (in dollars per share)	2.33	2.99	5.30
Outstanding at end of period (in dollars per share)	$ 2.63	$ 2.54	$ 3.37
Restricted Stock Units (RSUs)
Restricted Stock Outstanding
Beginning balance (in shares)	546,858	306,142	250,115
Granted (in shares)	85,575	553,657	375,542
Vested (in shares)	(436,282)	(222,835)	(115,622)
Canceled (in shares)	(163,100)	(90,106)	(203,893)
Ending balance (in shares)	33,051	546,858	306,142