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Secured Notes to Related Party - Additional Information (Details)				1 Months Ended			12 Months Ended
	Aug. 05, 2016 USD ($)	Aug. 02, 2016 USD ($) shares	Jul. 29, 2011 shares	Aug. 31, 2018 USD ($)	Aug. 31, 2016 USD ($)	Apr. 30, 2011 USD ($) Day shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Proceeds from convertible debt						$ 4,300,000
Amortization of debt discount							$ 1,050,000	$ 890,000	$ 773,000
Debt instrument, convertible, number shares of equity instruments \| shares							9,000,000.0
Convertible Notes
Debt Instrument [Line Items]
Convertible debt issuable in connection with private placement						$ 4,500,000
Debt instrument, interest rate						6.00%
Debt instrument, maturity date						May 02, 2021
Debt instrument conversion ratio multiple of principal						$ 1,000
Beneficial ownership after conversion						9.99%
Notice period associated with beneficial ownership percentage limitation convertible notes \| Day						61
Common shares registered for resale in connection with convertible notes \| shares			3,500,000
Debt instrument, term						10 years
Paid-in-kind interest							$ 400,000
Debt instrument, additional debt discount							400,000
Interest expense, debt, excluding amortization							400,000	400,000	400,000
Amortization of debt discount							1,100,000	900,000	800,000
Carrying value of debt							5,600,000
Debt instrument, face amount							7,200,000
Debt instrument, unamortized discount, total							$ 1,600,000
Convertible Notes \| Common Stock
Debt Instrument [Line Items]
Debt instrument, number of shares issued for convertible notes \| shares						1,250
Term Loan \| Tang Capital
Debt Instrument [Line Items]
Debt instrument, interest rate					8.00%
Debt instrument, term					2 years
Carrying value of debt								0
Debt agreement, maximum borrowing capacity					$ 100,000,000.0
Proceeds from issuance of long-term debt, total	$ 50,000,000.0
Proceeds from issuance of long-term debt, subject to achievement of corporate milestone		$ 50,000,000.0
Debt instrument, fee amount		$ 0
Debt instrument, number of warrants \| shares		0
Debt instrument, convertible, beneficial conversion feature		$ 0
Interest expense								$ 1,200,000	$ 2,800,000
Debt outstanding principal paid				$ 25,000,000.0
Debt accrued interest paid				$ 200,000