Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities:
Net loss	$ (43,129,000)	$ (23,705,000)	$ (22,333,000)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation	8,771,000	9,871,000	11,385,000
Amortization of intangible assets	809,000	0	166,000
Non-cash interest expense	444,000	0	0
Loss on lease due to restructuring	179,000	87,000	1,043,000
Pension and defined benefit plan cost	770,000	635,000	412,000
Stock-based compensation expense	9,037,000	5,364,000	3,946,000
Gain on sale of property and equipment	(20,000)	(131,000)	0
Impairment of property and equipment	240,000	1,389,000	0
Gain on sale of product line	0	(6,657,000)	0
Unrealized loss (gain) on foreign currency exchange rates	(150,000)	63,000	1,631,000
Release of tax valuation allowance	0	0	(170,000)
Release of tax liability	0	(1,518,000)	0
Provision for (recovery of) allowance on accounts receivable	10,000	(106,000)	281,000
Losses on write downs of inventory	2,309,000	397,000	541,000
Provision for warranties	303,000	383,000	1,327,000
Changes in operating assets and liabilities:
Trade and other accounts receivable	(7,981,000)	20,085,000	315,000
Inventories	2,568,000	(4,956,000)	5,251,000
Prepaid expenses and other assets	477,000	(372,000)	(35,000)
Pension asset	(1,067,000)	(584,000)	(650,000)
Accounts payable and accrued liabilities	8,842,000	(14,884,000)	5,031,000
Deferred revenue and customer deposits	2,356,000	630,000	2,362,000
Accrued employee compensation	609,000	(1,478,000)	(2,670,000)
Deferred tax liability	(154,000)	1,957,000	2,017,000
Defined benefit plan and other long-term liabilities	(229,000)	(827,000)	(470,000)
Net cash provided by (used in) operating activities	(15,006,000)	(14,357,000)	9,380,000
Investing activities:
Purchases of property and equipment	(5,817,000)	(5,956,000)	(4,143,000)
Proceeds from sale of property and equipment	20,000	133,000	0
Cash used in acquisition, net of cash acquired	(97,000)	0	0
Proceeds from sale of product line	1,500,000	20,486,000	0
Net cash provided by (used in) investing activities	(4,394,000)	14,663,000	(4,143,000)
Financing activities:
Principal payments on long-term debt and short-term borrowings	(32,000)	(45,000)	(18,845,000)
Proceeds from long-term debt and short-term borrowings, net of discount and issuance costs	42,991,000	0	3,040,000
Proceeds from sale of common stock, net of offering costs	0	0	9,564,000
Proceeds from issuance of common stock under equity compensation plans	326,000	841,000	875,000
Net cash provided by (used in) financing activities	43,285,000	796,000	(5,366,000)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	878,000	(525,000)	179,000
Increase in cash, cash equivalents and restricted cash	24,763,000	577,000	50,000
Cash, cash equivalents and restricted cash, beginning of period	25,359,000	24,782,000	24,732,000
Cash, cash equivalents and restricted cash at end of year	50,122,000	25,359,000	24,782,000
Cash paid for:
Interest	82,000	75,000	245,000
Income taxes	2,306,000	2,551,000	3,475,000
Supplemental schedule of noncash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	1,633,000	181,000	345,000
Common stock issued for acquisition of Nesscap	25,294,000	0	0
Amounts in escrow related to sale of product line	$ 0	$ 1,500,000	$ 0