Commitments and Contingencies - Litigation (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) installment	Dec. 31, 2018 USD ($)	Jul. 26, 2018 $ / shares	Jul. 12, 2018 $ / shares	Apr. 30, 2018 $ / shares
Employee Arrangements and Other Compensation
Severance benefits payable	$ 1.7
Purchase Commitments
Purchase commitments	0.8
August 2017 investor warrants
Purchase Commitments
Exercise price of warrants (in dollars per share) | $ / shares					$ 1,575.00
Series B convertible preferred stock
Purchase Commitments
Conversion price (in dollars per share) | $ / shares					$ 189,000.00
Accrued Liabilities [Member]
Employee Arrangements and Other Compensation
Accrued performance bonuses	0.6	$ 0.3
Alpha litigation | August 2017 investor warrants | Maximum
Purchase Commitments
Exercise price of warrants (in dollars per share) | $ / shares				$ 420.00
Alpha litigation | Series B convertible preferred stock | Maximum
Purchase Commitments
Conversion price (in dollars per share) | $ / shares				$ 50,400.00
Iroquois litigation | April 3, 2018 investor warrants
Purchase Commitments
Exercise price of warrants (in dollars per share) | $ / shares			$ 189.00
Iroquois litigation | Series D convertible preferred stock
Purchase Commitments
Conversion price (in dollars per share) | $ / shares			$ 22,680.00
Fulfillium litigation
Purchase Commitments
Amount awarded in cash	1.5
Cash paid	0.5
Amount payable	$ 1.0
Number of quarterly installments | installment	4
Contingent loss settlement	$ 1.5