Stockholders' Equity - Additional Information (Details)		1 Months Ended		12 Months Ended
		Apr. 30, 2016 shares	Jan. 31, 2010 USD ($) shares	Dec. 31, 2019 USD ($) installment $ / shares shares	Dec. 31, 2018 USD ($) installment $ / shares shares	Dec. 31, 2017 shares
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Stock based compensation expense | $				$ 1,500,000	$ 600,000
Stock-based compensation expense expected to be recognized | $				$ 4,000,000	$ 4,000,000
Carilion Clinic
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Senior convertible promissory notes principal amount converted | $			$ 5,000,000.0
Accrued interest converted | $			$ 1,200,000
Percentage of dividend payable on series A convertible preferred stock			6.00%
Preferred stock liquidation preference value | $			$ 6,200,000
Carilion Clinic | Series A Convertible Preferred Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Preferred stock issued in exchange of notes payable (in shares)			1,321,514
Stock Options
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Vesting period				4 years
Weighted average grant date fair value of options granted (in dollars per share) | $ / shares				$ 2.32	$ 2.07
Options outstanding, remaining contractual term				3 years 5 months
Weighted average remaining service period related to compensation recognition				2 years 10 months 30 days
Unamortized stock option expense to be recognized | $				$ 2,800,000
Restricted Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares issued (in shares)				217,000	280,000
Share-based compensation vesting installments | installment				3	3
Share-based Compensation, vested (in shares)				63,000
Share-based compensation, issuable upon vesting (in shares)				63,000
Share-based compensation, percentage				150.00%
Share-based compensation, revenue and operating Income (in shares)				42,000
Shares vested (in shares)				194,333	182,500
Restricted Stock | Employees
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares issued (in shares)				280,000
Restricted Stock and Restricted Stock Units
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Weighted average remaining service period related to compensation recognition				2 years
Shares issued (in shares)				291,600	296,287
Share-based Compensation, vested (in shares)				502,102	458,620	489,698
Shares vested (in shares)				210,619	312,365
Unamortized restricted stock and restricted stock units expense to be recognized | $				$ 1,200,000
Restricted Stock Units (RSUs)
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Share-based Compensation, vested (in shares)				37,546
Restricted Stock Units (RSUs) | Member of Board of Directors
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares issued (in shares)				11,600	16,286
Shares vested (in shares)				16,286	129,865
2016 Equity Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares available for future grant (in shares)		3,500,000
Stock option contractual term		10 years
Common Stock
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Preferred stock to common stock conversion (in shares)				1,321,514
Shares of common stock dividends (in shares)	[1]			(770,454)

[1] The stock dividends payable in connection with the Series A Convertible Preferred Stock were issued at the request of Carilion. See Note 11 - Stockholders' Equity for more information.