Stockholders' Equity - Restricted Stock Units (Details)	9 Months Ended
	Sep. 30, 2019 $ / shares shares
Restricted Stock Units
Outstanding at beginning of period (in shares) | shares	292,871
Granted (in shares) | shares	450,000
Canceled/forfeited (in shares) | shares	(151,993)
Outstanding at end of period (in shares) | shares	563,353
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 3.78
Granted (in dollars per share) | $ / shares	0.42
Canceled/forfeited (in dollars per share) | $ / shares	2.90
Outstanding at end of period (in dollars per share) | $ / shares	$ 1.26
Weighted Average Remaining Contractual Life (in years)
Outstanding at end of period	9 years 1 month
Restricted Stock Units
Restricted Stock Units
Outstanding at beginning of period (in shares) | shares	546,858
Granted (in shares) | shares	27,187
Released (in shares) | shares	(377,894)
Canceled/forfeited (in shares) | shares	(152,441)
Outstanding at end of period (in shares) | shares	43,710
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 2.54
Granted (in dollars per share) | $ / shares	1.04
Released (in dollars per share) | $ / shares	2.51
Canceled/forfeited (in dollars per share) | $ / shares	2.32
Outstanding at end of period (in dollars per share) | $ / shares	$ 2.62
Weighted Average Remaining Contractual Life (in years)
Outstanding at end of period	1 year 2 months