Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Mar. 31, 2018

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information

(In thousands, except per share data)	1st Quarter			2nd Quarter			3rd Quarter			4th Quarter
Year Ended March 31, 2018
Net sales
Systems	$	62,093		$	60,316		$	99,418		$	103,522
Services	10,591			10,651			11,422			9,871
Total net sales	72,684			70,967			110,840			113,393
Cost of sales:
Systems	41,426			38,179			52,502			53,247
Services	4,838			6,256			5,182			5,424
Total cost of sales	46,264			44,435			57,684			58,671
Gross profit	26,420			26,532			53,156			54,722
Net income	2,902			4,260			33,973			75,088
Basic net income per share	0.09			0.13			0.99			2.19
Diluted net income per share	0.08			0.12			0.94			2.10
Year Ended April 1, 2017
Net sales
Systems	$	38,200		$	21,442		$	25,427		$	40,029
Service	9,468			8,216			8,352			9,889
Total net sales	47,668			29,658			33,779			49,918
Cost of sales:
Systems	22,422			14,146			17,283			27,499
Service	4,438			4,532			5,048			4,189
Total cost of sales	26,860			18,678			22,331			31,688
Gross profit	20,808			10,980			11,448			18,230
Net loss	(118		)	(9,675		)	(9,693		)	(17,923		)
Basic net loss per share	—			(0.30		)	(0.29		)	(0.54		)
Diluted net loss per share	—			(0.30		)	(0.29		)	(0.54		)