Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cash and cash equivalents	$ 25,116,000				$ 26,169,000				$ 25,116,000	$ 26,169,000	$ 16,142,000
Impairment of intangible assets											100,000
Asset impairment charges									0	0	0
Money market funds, at cost					1,807,000					1,807,000
Additional paid-in capital	1,287,336,000				1,285,787,000				1,287,336,000	1,285,787,000
Accounts receivable	14,295,000				14,837,000				14,295,000	14,837,000
Prepaid expenses included in other assets					1,200,000					1,200,000
Other current assets	2,378,000				6,851,000				2,378,000	6,851,000
Capitalized costs for internally developed software									0
Advertising expense									600,000	400,000	900,000
Cost of services									4,874,000	4,123,000	4,232,000
Net income (loss)	$ (2,605,000)	$ (3,113,000)	$ (2,023,000)	$ (3,896,000)	(6,716,000)	$ 886,000	$ (281,000)	$ (1,068,000)	$ (11,637,000)	$ (7,179,000)	$ (12,155,000)
Net loss per share — basic and diluted (usd per share)	$ (0.38)	$ (0.45)	$ (0.29)	$ (0.56)					$ (1.69)	$ (1.02)	$ (1.66)
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)									455,498	295,366	309,309
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)									97,500	97,500	97,500
Fair Value, Inputs, Level 1
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cash and cash equivalents, fair value					1,807,000					$ 1,807,000
United States
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cash and cash equivalents	$ 19,200,000				21,600,000				$ 19,200,000	21,600,000
Foreign
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cash and cash equivalents	5,900,000				4,600,000				5,900,000	4,600,000
Software License Arrangement
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Impairment of intangible assets									$ 0	$ 0	$ 100,000
Two major customers | Accounts Receivable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Concentration risk percentage									22.00%	20.00%
Other Current Assets
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Prepaid expenses included in other assets	1,100,000				1,200,000				$ 1,100,000	$ 1,200,000
Other current assets	1,300,000				900,000				$ 1,300,000	900,000
Tecnonet | Other Current Assets
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Accounts receivable					4,800,000					4,800,000
Minimum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Standard product warranty period									90 days
Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Standard product warranty period									3 years
Restricted Time Deposit [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Restricted investments	300,000				5,200,000				$ 300,000	5,200,000
Certificates of deposit					5,000,000					5,000,000
Security deposit	$ 300,000				$ 200,000				300,000	$ 200,000
Service Life
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Cost of services									200,000
Net income (loss)									$ (200,000)
Net loss per share — basic and diluted (usd per share)									$ 0.03
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stipulation of settlement, payment to plaintiff, warrants (shares)											250,000
Additional paid-in capital											$ 1,600,000
Expected volatility rate											41.00%
Risk free interest rate											1.50%
Stipulation of settlement, payment to plaintiff, warrants, term											5 years
Warrants, fair value per share (usd per share)											$ 6.59
Warrants exercised (shares)									0	0	152,500
Warrants outstanding (shares)											97,500
Warrant exercise price (usd per share)											$ 8.80