Stockholders' Equity - Outstanding Options Granted to Consultants for Sales and Pre-marketing Services (Details)	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 0
Options exercisable at the end of the year (in shares)	452,264
Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	20,287
Options exercisable at the end of the year (in shares)	20,182
February 2013 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	1,500
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 12.470
Options exercisable at the end of the year (in shares)	1,500
Exercisable through	2023-02
August 2013 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	4,000
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 21.140
Options exercisable at the end of the year (in shares)	4,000
Exercisable through	2023-08
March 2014 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	3,750
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 39.860
Options exercisable at the end of the year (in shares)	3,750
Exercisable through	2024-03
May 2014 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	3,700
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 22.010
Options exercisable at the end of the year (in shares)	3,700
Exercisable through	2024-05
November 2014 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	4,218
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 21.660
Options exercisable at the end of the year (in shares)	4,218
Exercisable through	2024-11
May 2015 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	1,137
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 19.510
Options exercisable at the end of the year (in shares)	1,137
Exercisable through	2025-05
February 2016 | Consultants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options for shares of common stock (in shares)	1,982
Granted, weighted average exercise price (in dollars per share) | $ / shares	$ 16.870
Options exercisable at the end of the year (in shares)	1,877
Exercisable through	2026-02