RESTATEMENT - Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 32,415	$ 16,596
Short term investments	40,885	61,678
Trade accounts receivable, net	4,969	5,080
Inventories, net of provision for obsolescence of $398 and $439	5,598	5,297
Prepaid expenses and other current assets	1,449	1,184
Total current assets	85,316	89,835
Property and equipment, net	6,031	5,788
Intangibles	190	191
Deposits	80	73
Other assets	239	41
Total assets	91,856	95,928
Current liabilities:
Accounts payable	1,504	1,423
Accrued expenses and other current liabilities	5,587	5,865
Joint and several payroll liability	1,014	713
Accrued severance and related	511	610
Total current liabilities	8,616	8,611
Note payable	140	140
Long term lease liability	75
Other long-term liabilities	194	0
Total liabilities	9,025	8,751
STOCKHOLDERS' EQUITY
Common stock	34	34
Additional paid-in capital	54,182	52,920
Retained earnings	28,615	34,223
Total stockholders’ equity	82,831	87,177	$ 21,469	$ 22,032
Total liabilities and stockholders’ equity	91,856	$ 95,928
As Originally Reported
ASSETS
Cash and cash equivalents	32,415
Short term investments	40,885
Trade accounts receivable, net	4,931
Inventories, net of provision for obsolescence of $398 and $439	5,598
Prepaid expenses and other current assets	1,411
Total current assets	85,240
Property and equipment, net	6,031
Intangibles	190
Deposits	80
Other assets	162
Total assets	91,703
Current liabilities:
Accounts payable	1,504
Accrued expenses and other current liabilities	5,460
Joint and several payroll liability	0
Accrued severance and related	511
Total current liabilities	7,475
Note payable	140
Long term lease liability	75
Other long-term liabilities	0
Total liabilities	7,690
STOCKHOLDERS' EQUITY
Common stock	34
Additional paid-in capital	53,147
Retained earnings	30,832
Total stockholders’ equity	84,013
Total liabilities and stockholders’ equity	91,703
Material Corrections | Adjustments
ASSETS
Cash and cash equivalents	0
Short term investments	0
Trade accounts receivable, net	38
Inventories, net of provision for obsolescence of $398 and $439	0
Prepaid expenses and other current assets	38
Total current assets	76
Property and equipment, net	0
Intangibles	0
Deposits	0
Other assets	77
Total assets	153
Current liabilities:
Accounts payable	0
Accrued expenses and other current liabilities	127
Joint and several payroll liability	1,014
Accrued severance and related	0
Total current liabilities	1,141
Note payable	0
Long term lease liability	0
Other long-term liabilities	194
Total liabilities	1,335
STOCKHOLDERS' EQUITY
Common stock	0
Additional paid-in capital	1,035
Retained earnings	(2,217)
Total stockholders’ equity	(1,182)
Total liabilities and stockholders’ equity	$ 153