Fair Value Measurements (Details) - Fair Value Measurements, Recurring [Member] - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Financial Assets:
Total		$ 3
Financial Liabilities:
Common stock warrant liability	[1]
Total		3
Corporate Fixed Income Debt Securities [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Money Market Funds [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 1 [Member]
Financial Assets:
Total
Financial Liabilities:
Common stock warrant liability	[1]
Total
Fair Value Inputs, Level 1 [Member] | Corporate Fixed Income Debt Securities [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 1 [Member] | Money Market Funds [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 2 [Member]
Financial Assets:
Total
Financial Liabilities:
Common stock warrant liability	[1]
Total
Fair Value Inputs, Level 2 [Member] | Corporate Fixed Income Debt Securities [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 2 [Member] | Money Market Funds [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 3 [Member]
Financial Assets:
Total
Financial Liabilities:
Common stock warrant liability	[1]
Total
Fair Value Inputs, Level 3 [Member] | Corporate Fixed Income Debt Securities [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value
Fair Value Inputs, Level 3 [Member] | Money Market Funds [Member]
Financial Assets:
Held-to-maturity Securities, Fair Value

[1] The change in the fair value of the common stock warrant and convertible notes payable for the twelve months ended December 31, 2019 and 2018 was recorded as a decrease to other income (expense) and interest expense of $0 and $1, respectively, in the statements of operations and comprehensive loss.