Description of Business and Basis of Presentation (Details Textual) $ / shares in Units, shares in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) manufacturing_location contract_manufacturer segment product_line	Dec. 31, 2016 USD ($) reporting_unit	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Description of Business and Basis of Presentation (Textual) [Abstract]
Manufacturing locations | manufacturing_location		2
Operating segments | segment		1
Number of product lines | product_line		2
Cumulative valuation allowance		$ 88,400,000
Deferred tax liability recorded associated with unremitted earnings of foreign subsidiary no longer considered indefinitely reinvested		4,900,000
Undistributed earnings of Swiss subsidiary		$ 97,600,000
Number of reporting units | reporting_unit			1
Warranty period, minimum, in years		1 year
Warranty period, maximum, in years		8 years
Accrued warranty liability		$ 1,298,000	$ 1,213,000	$ 1,206,000	$ 1,288,000
Deferred revenue and customer deposits		$ 6,489,000	3,967,000
Term of agreement		10 years
Cash and cash equivalents		$ 20,894,000	$ 25,359,000
Working capital amount		46,900,000
Accounting Standards Update 2016-09, Excess Tax Benefit Component
Description of Business and Basis of Presentation (Textual) [Abstract]
Cumulative valuation allowance		10,000,000
Deferred tax assets related to stock-based compensation		10,000,000
Accounting Standards Update 2016-18
Description of Business and Basis of Presentation (Textual) [Abstract]
Restricted cash balance				$ 400,000	$ 400,000
Stock Purchase Agreement | SDIC Fund Management Co., Ltd. | Subsequent Event | Scenario, Forecast
Description of Business and Basis of Presentation (Textual) [Abstract]
Number of shares to be sold pursuant to stock purchase agreement | shares	7.4
Sales price per share | $ / shares	$ 6.32
Aggregate purchase price	$ 46,600,000
Revolving Credit Facility | East West Bank
Description of Business and Basis of Presentation (Textual) [Abstract]
Revolving line of credit		25,000,000
Drawings under revolving line of credit		0
Amount available under revolving line of credit		$ 14,900,000
Revenue from Production Type Contracts | Maximum
Description of Business and Basis of Presentation (Textual) [Abstract]
Percentage of revenue (less than five percent)		5.00%
Revenue | Maximum | Non-product Sale Arrangements
Description of Business and Basis of Presentation (Textual) [Abstract]
Percentage of revenue (less than five percent)		5.00%
China
Description of Business and Basis of Presentation (Textual) [Abstract]
Number of contract manufacturers | contract_manufacturer		2