Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Cash Flows [Abstract]
Consolidated net income	$ 11,248,000	$ 1,220,000	$ 8,801,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	27,283,000	23,516,000	17,961,000
Amortization expense, intangible assets	3,968,000	1,581,000	103,000
Stock-based compensation to employees and directors	4,891,000	3,526,000	4,035,000
Deferred income taxes, net	7,719,000	1,483,000	3,741,000
Amortization of Financing Costs	0	21,000	0
(Gain) loss on investment in precious metals	(201,000)	1,183,000	1,269,000
Gain (Loss) on Investment in Cryptocurrency	0	152,000	8,000
Impairment of cost method investment	2,850,000	0	0
Restructuring reversals	0	0	(360,000)
Loss on Cash Flow Hedge Ineffectiveness	0	124,000	0
Redemption Premium	0	850,000	0
Other	356,000	9,000	(16,000)
Changes in operating assets and liabilities, net of acquisitions:
Restricted cash	0	0	1,000,000
Accounts receivable, net	(10,006,000)	3,463,000	(2,916,000)
Inventories, net	1,105,000	6,166,000	835,000
Prepaid inventories, net	(801,000)	1,903,000	(1,410,000)
Prepaids and other current assets	2,389,000	(1,338,000)	(1,455,000)
Other long-term assets, net	(786,000)	66,000	26,000
Accounts payable	(18,823,000)	10,482,000	21,652,000
Accrued liabilities	16,936,000	(4,153,000)	15,607,000
Deferred revenue	(9,164,000)	2,493,000	11,130,000
Other long-term liabilities	600,000	1,769,000	823,000
Net cash provided by operating activities	39,564,000	54,516,000	80,834,000
Cash flows from investing activities:
Proceeds from sale of precious metals	1,610,000	0	0
Investment in precious metals	(1,633,000)	0	(2,496,000)
Investment in cryptocurrency	0	0	(300,000)
Equity method investment	0	(152,000)	(250,000)
Disbursements for note receivable	(3,668,000)	(5,000,000)	0
Cost method investments	(4,750,000)	(7,000,000)	0
Acquisitions of businesses, net of cash acquired	1,248,000	(10,601,000)	0
Expenditures for fixed assets, including internal-use software and website development	(72,281,000)	(59,513,000)	(41,346,000)
Other	27,000	(165,000)	(38,000)
Net cash used in investing activities	(79,447,000)	(82,431,000)	(44,430,000)
Cash flows from financing activities:
Payments on capital lease obligations	0	(362,000)	(325,000)
Paydown on direct financing arrangement	(54,000)	(308,000)	(282,000)
Payments on finance obligations	(1,906,000)	(104,000)	0
Payments on interest swap	(563,000)	(57,000)	0
Proceeds from finance obligations	11,399,000	5,698,000	0
Proceeds from short-term debt	0	5,500,000	0
Payments on short-term debt	0	(750,000)	0
Proceeds from long-term debt	36,273,000	9,488,000	0
Change in restricted cash	0	150,000	0
Proceeds from exercise of stock options	819,000	269,000	511,000
Proceeds from rights offering, net of offering costs	7,591,000	0	0
Purchase of treasury stock	(840,000)	(2,367,000)	(2,301,000)
Payment of debt issuance costs	0	(621,000)	(1,031,000)
Net cash provided by (used in) financing activities	52,719,000	16,536,000	(3,428,000)
Net (decrease) increase in cash and cash equivalents	12,836,000	(11,379,000)	32,976,000
Cash and cash equivalents, beginning of year	170,262,000	181,641,000	148,665,000
Cash and cash equivalents, end of year	183,098,000	170,262,000	181,641,000
Cash paid during the period:
Interest paid	1,269,000	224,000	47,000
Taxes paid	1,338,000	273,000	76,000
Non-cash investing and financing activities:
Fixed assets, including internal-use software and website development, costs financed through accounts payable and accrued liabilities	2,219,000	6,290,000	1,410,000
Equipment acquired under capital lease obligations	0	362,000	325,000
Capitalized interest cost	105,000	157,000	26,000
Acquisition of businesses through stock issuance	0	18,149,000	0
Change in value of cash flow hedge	(659,000)	1,265,000	1,008,000
Note receivable converted to cost method investment	$ 2,850,000	$ 0	$ 0