Summary of Significant Accounting Policies - Narrative (Details)		3 Months Ended		6 Months Ended
		Jun. 30, 2018 USD ($) customer $ / shares	Jun. 30, 2017 USD ($) customer	Jun. 30, 2018 USD ($) customer $ / shares	Jun. 30, 2017 USD ($) customer	Dec. 31, 2017 USD ($)
Revenues attributable to sales [Line Items]
Conversion price (USD per share) | $ / shares		$ 8.50		$ 8.50
Merger related costs		$ 906,000		$ 1,300,000
Warranty reserves		$ 402,000		$ 402,000		$ 350,000
Percentage of net revenue		35.90%	35.50%	38.20%	35.10%
Numbers of customers | customer		2	2	2	2
Revenues	[1]	$ 7,917,000	$ 8,337,000	$ 15,754,000	$ 16,040,000
Line of Credit Maintained				$ 1,000,000
Avnet
Revenues attributable to sales [Line Items]
Percentage of net revenue		27.70%	29.40%	27.60%	27.40%
Significant Customers | Avnet
Revenues attributable to sales [Line Items]
Percentage of net revenue				38.20%

[1] Represents the portfolio of available for sale securities that is included in restricted investments and short-term investments in the Company’s condensed consolidated balance sheets