CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015
Current assets:
Cash and cash equivalents	$ 79,293	$ 68,835
Restricted cash	5,596	6,193
Short-term investments, at fair value	7,694	24,533
Accounts receivable, net of allowances of $250 and $333 at September 30, 2015 and March 31, 2015, respectively	20,873	22,124
Unbilled costs and fees	3,478	1,848
Inventories, net	38,329	40,983
Prepaid expenses and other current assets	8,823	10,701
Deferred income taxes	2,486	2,486
Total current assets	166,572	177,703
Equipment and leasehold improvements, net	7,117	8,711
Restricted cash	231	208
Deferred income taxes	5,952	5,952
Other assets, net	301	534
Total assets	180,173	193,108
Current liabilities:
Accounts payable	4,747	7,200
Accrued salaries and benefits	4,549	6,769
Accrued warranty costs	200	159
Deferred revenue	8,653	7,355
Customer deposits	11,557	13,956
Other current liabilities	4,579	5,736
Total current liabilities	34,285	41,175
Deferred revenue	3,344	1,019
Other long-term liabilities	622	507
Total liabilities	$ 38,251	$ 42,701
Stockholders' equity:
Preferred stock, no par value, 100,000 shares authorized; no shares issued
Common stock, $0.66 2/3 par value, 20,000,000 shares authorized; 7,163,642 and 7,193,247 shares issued and outstanding at September 30, 2015 and March 31, 2015, respectively	$ 4,775	$ 4,795
Capital in excess of par value	2,126	3,334
Accumulated other comprehensive loss, net	(7)	(11)
Retained earnings	135,028	142,289
Total stockholders' equity	141,922	150,407
Total liabilities and stockholders' equity	$ 180,173	$ 193,108

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.