Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Significant Accounting Policies [Abstract]

Summary of Activity Related to Warranty Liability Included in Other Current Liabilities

	Twelve Months Ended
	December 31,
	2018		2017
Beginning balance	$	468	$	584
Warranty accruals and adjustments		132		136
Warranty claims		(177)		(252)
Ending balance	$	423	$	468

Schedule of Estimated Future Amortization Expense

Fiscal Years Ending December 31,	Total Amortization
2019	$	32
2020		9
2021		8
2022		8
2023		8
Later years		16
	$	81

Schedule of Potentially Dilutive Common Stock Equivalents

	Twelve Months Ended
	December 31,
	2018	2017
Options	4,678,420	4,768,838
Warrants	9,055,773	5,081,449
Convertible preferred stock	7,545,333	7,545,333
Total potentially dilutive common stock equivalents	21,279,526	17,395,620

Reconciliation of the Level 3 Warrant Liability Measured and Recorded at Fair Value on a Recurring Basis

	Estimated Fair Value
Balance as of January 1, 2018	$	784
Fair value of warrants issuance during period		2,907
Change in fair value of warrant liability, net		(2,194)
Balance as of December 31, 2018	$	1,497