CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2017	Apr. 01, 2016
Cash flows from operating activities:
Net income	$ 2,641,000	$ 1,078,000
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	919,000	610,000
Deferred income taxes, net	28,000	269,000
Provision for doubtful accounts	8,000	31,000
Stock-based compensation	476,000	207,000
Accretion and fair value adjustments of contingent consideration	167,000	(28,000)
Changes in operating assets and liabilities, net of effects from business acquisitions:
Accounts receivable	(963,000)	(2,259,000)
Costs and estimated earnings in excess of billings on uncompleted contracts	(10,191,000)	(2,231,000)
Other receivables	471,000	(20,000)
Prepaid expenses and other current assets	(559,000)	(236,000)
Other assets	25,000	10,000
Accounts payable	2,475,000	(636,000)
Accrued liabilities	3,377,000	(864,000)
Billings in excess of costs and estimated earnings on uncompleted contracts	(256,000)	2,410,000
Deferred lease obligations	(6,000)	32,000
Net cash provided by operating activities	(1,388,000)	(1,627,000)
Cash flows from investing activities:
Purchase of equipment and leasehold improvements	(583,000)	(257,000)
Cash paid for acquisitions, net of cash acquired		(8,857,000)
Net cash used in investing activities	(583,000)	(9,114,000)
Cash flows from financing activities:
Payments on contingent consideration	(1,508,000)
Payments on notes payable	(1,272,000)	(939,000)
Principal payments on capital lease obligations	(121,000)	(128,000)
Proceeds from stock option exercise	1,300,000	47,000
Proceeds from sales of common stock under employee stock purchase plan	344,000	113,000
Net cash (used in) provided by financing activities	(1,257,000)	(907,000)
Net increase (decrease) in cash and cash equivalents	(3,228,000)	(11,648,000)
Cash and cash equivalents at beginning of period	22,668,000	16,487,000
Cash and cash equivalents at end of period	19,440,000	4,839,000
Cash paid during the period for:
Interest	33,000	49,000
Income taxes	249,000	686,000
Supplemental disclosures of noncash investing and financing activities:
Issuance of notes payable related to business acquisitions		4,569,000
Issuance of common stock related to business acquisitions		2,230,000
Equipment acquired under capital leases	$ 32,000	$ 884,000