Summary of Significant Accounting Policies (Details) $ in Thousands	9 Months Ended
Sep. 30, 2019 USD ($) Institution	Dec. 31, 2018 USD ($)
Concentration of Credit Risk and Others Risks and Uncertainties [Abstract]
Number of financial institutions holding company's cash \| Institution	2
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	$ 2,572	$ 7,611
Adjusted Cost	3,435	4,366
Unrealized Gains	2	0
Unrealized Losses	0	0
Fair Value	3,437	4,366
Adjusted Cost	5,191	9,414
Fair Value	5,193	9,414
Cash [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	1,756	5,048
Fair Value	1,756	5,048
Cash and Cash Equivalents	1,756	5,048
Mutual Funds [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	624	1,107
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	624	1,107
U.S. Agency Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Adjusted Cost	2,811	3,259
Unrealized Gains	2	0
Unrealized Losses	0	0
Fair Value	2,813	3,259
Recurring [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	2,572	7,611
Cash and Cash Equivalents	2,572	7,611
Investments Available for Sale	2,621	1,803
Recurring [Member] \| Cash [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	1,756	5,048
Cash and Cash Equivalents	1,756	5,048
Recurring [Member] \| Level 1 [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	816	2,563
Cash and Cash Equivalents	816	2,563
Investments Available for Sale	2,621	1,803
Recurring [Member] \| Level 1 [Member] \| Mutual Funds [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	624	1,107
Cash and Cash Equivalents	624	1,107
Investments Available for Sale	0	0
Recurring [Member] \| Level 1 [Member] \| U.S. Agency Securities [Member]
Cash and available-for-sale securities adjusted cost, gross unrealized gains, gross unrealized losses and fair value by significant investment category [Abstract]
Fair Value	192	1,456
Cash and Cash Equivalents	192	1,456
Investments Available for Sale	2,621	$ 1,803
2013 to 2016 [Member]
Deferred Revenue [Abstract]
Total contractual payments received	$ 10,000

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